qmb mt and final

Exam 1. 1. All continuous random variables are normally distributed. False. 2. The actual weight of hamburger patties is an example of a continuous random variable. True 3. The college of business administration at acorn University offers a major in finance. Based on historical records, 30% of the college of business students major in Finance. A random sample of 20 students is selected. What is the probability that exactly 3 of the selected students are majoring in Finance? .0716 4. Assume that we have selected a random sample of 25 units from a normally distributed large population. If u = 15, and c2=4, what is the probability that we will obtain a sample mean of less than 14? .0062 5. The normal approximation of the binomial distribution is appropriate when. Np> 5 and n(1-p) >5 6. A newly married couple plans to have four children. Suppose that boys and girls are equal likely each time a child is born. What is the probability the couple will have no more than 2 boys? 62.5% 7. A random variable is said to be discrete if: Its outcome are countable 8. The mean life of pair of shoes is 40 months with a standard deviation of 8 months. If the life of the shoes is normally distributed, how many pairs of shoes out of one million will need replacement before 36 months? 308,500 9. If the sampled population has a mean of 48 and standard deviation 16, then the mean and the standard deviation for the sampling distribution x for n=16 48 and 4 10. The MPG (MILES PER GALLON) for a mid-size car is normally distributed with a mean of 32 and a standard deviation of .8. what is the probability that the MPG for a selected mid-size car would be less that 33.2? 93.32% 11. If the random variable X has a mean of u and a standard deviation g, then (X-u)/g) has a mean and standard deviation respectively. 0 and 1 12. For a binomial probability experiment, with n=150 and p=.2, it is appropriate to use the normal approximation to the binomial distribution. TRUE 13. A computer system uses 4 bits address size to access all its devices. What is the total number of devices this system can talk to? 16 14. The standard deviation of all possible sample proportions increases as the sample size increases.

FALSE 15. The college of business Administration at Acorn University offers a major in Finance based on historical records, 30% of the college of business students major in finance. A random sample of 20 students is selected. What are the mean and then standard deviation of this distribution? 6 and 2.05 16. The number of defective pencils in a lot of 1000 is an example of a continuous random variable. FALSE 17. The ----------- distribution would most likely be used to describe the distribution of time between arrivals of customers at the grocery store. Exponential 18. The sampling distribution of the sample mean is developed by repeatedly taking samples of size n and computing the sample means and reporting the resulting sample means in the form of a probability distribution. TRUE 19. A students grade on an examination was transformed to a z value which is negative. Therefore, we know that he scored. Below the mean 20. Which of the following statements is not a property of the normal probability distribution? 95.44% of all possible observed values of the random variable x are within plus or minus three standard deviation of the population mean. 21. If the random variable of x is normally distributed, 68.26% of all possible observed values of x will be within two standard deviations of the mean. FALSE 22. The relationship between the standard normal random variable Z and normal random variable X is that: c. The standard normal variable Z counts the number of standard deviations that the value of the normal random variable X is away from its mean. 23. A standard normal distribution has a mean of ---------- and standard deviation of -------. ZERO, ONE. 24. Another name for the normal distribution is (are Both A and B. 25. Which of the following is a valid probability value for discrete random variable? .23.

View Results

Question 1

(4 points)

A confidence interval increases in width as Student response: Percent Correct Student Answer Choices Value Response Response

0.0% 0.0% 0.0% 100.0%

a. The level of confidence increases b. n decreases c. s increases d. All of the above

Score:

4/4

Question 2

(4 points)

In a manufacturing process a random sample of 9 bolts manufactured has a mean length of 3 inches with a variance of .09. What is the 90% confidence interval for the true mean length of the bolt? Student response: Percent Value 0.0% 0.0% 0.0% 100.0% 0.0% Correct Response Student Response Answer Choices a. 2.8355 to 3.1645 b. 2.5065 to 3.4935 c. 2.4420 to 3.5580

d. 2.8140 to 3.1860 e. 2.9442 to 3.0558

Score:

4/4

Question 3

(4 points)

For the following hypothesis test where H0: 10 vs. Ha: > 10, we reject H0 at level of significance ? and conclude that the true mean is greater than 10 when the true mean is really 8. Based on this information we can state that we have: Student response: Percent Correct Student Answer Choices Value Response Response 100.0% 0.0% 0.0% 0.0% a. Made a Type I error b. Made a Type II error c. Made a correct decision d. Increased the power of the test

Score:

4/4

Question 4

(4 points)

The power of a statistical test is the probability of rejecting the null hypothesis when it is true. Student response: Percent Value 0.0% Correct Response Student Response Answer Choices a. True

100.0%

b.

False

Score:

4/4

Question 5

(4 points)

When the level of confidence and sample standard deviation remain the same, a confidence interval for a population mean based on a sample of n = 100 will be ______________ a confidence interval for a population mean based on a sample of n = 50. Student response: Percent Value 0.0% 100.0% 0.0% Correct Response Student Response Answer Choices a. b. c. Wider than Narrower than Equal to

Score:

4/4

Question 6

(4 points)

When the null hypothesis is true, there is no possibility of making a Type I error. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 7

(4 points)

What sample size would be required to estimate to within 3 with 95% confidence if the population standard deviation is 24.5? Student response: Percent Value 0.0% 0.0% 100.0% 0.0% 0.0% Correct Response Student Response Answer Choices a. b. c. d. e. 769 124 257 91 2321

Score:

4/4

Question 8

(4 points)

According to a recent major survey, 70% of the respondents indicated that there is too much violence on TV. For a random sample of 40 people, what is the 95% confidence interval of the proportion of people who feel that there is too much violence on TV? Student response: Percent Value 0.0% 0.0% 0.0% 100.0% 0.0% Correct Response Student Response Answer Choices a. b. c. d. e. .70 .12 .70 .03 .70 .90 .70 .14 .70 .07

Score:

4/4

Question 9

(4 points)

Alpha ( ) is the probability that the test statistic would assume a value as or more extreme than the observed value of the test. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 10

(4 points)

The following list represents a sample of the ages of the soldiers enlisting in the military: 19, 22, 23, 19, 21, 22, 19, 23, 21. Assume that the population standard deviation is known to be 2 years. Construct a 99% confidence interval for the average age of the soldier enlisting in the military. Student response: Percent Value 0.0% 0.0% 0.0% 100.0% 0.0% Correct Response Student Response Answer Choices a. 17.92 to 24. 08 b. 15.85 to 26.15 c. 18.76 to 23.24

d. 19.28 to 22.72 e. 19.42 to 22.58

Score:

4/4

Question 11

(4 points)

If a one-sided null hypothesis for a single mean cannot be rejected at a given significance level, then the corresponding two-sided null hypothesis (i.e., the same sample size, the same standard deviation, and the same mean) will_________ be rejected at the same significance level.

Student response: Percent Value 0.0% 0.0% 100.0%

Correct Response

Student Response

Answer Choices a. b. c. Always Sometimes Never

Score:

0/4

Question 12

(4 points)

The null hypothesis always includes an equal (=) sign. Student response: Percent Value 100.0% 0.0% Correct Response Student Response Answer Choices a. b. True False

Score:

0/4

Question 13

(4 points)

The average waiting time per customer at a fast food restaurant has been 7.5 minutes. The customer waiting time has a normal distribution. The manager claims that the use of a new cashier system will decrease the average customer waiting time in the store. A random sample of 12 customer transactions has been recorded. At a significance level of .05, what is the rejection point condition? We would reject the null hypothesis if: Student response: Percent Value 0.0% 0.0% 0.0% 100.0% 0.0% Correct Response Student Response Answer Choices a. b. c. d. e. Z < -1.645 Z > 1.645 t > 1.796 t < -1.796 t < -1.782

Score:

4/4

Question 14

(4 points)

What value(s) of alpha would we reject H0 for greater than the mean 10 if = 11, s = 2, and n = 36? Student response: Percent Value 100.0% 0.0% 0.0% Correct Response Student Response Answer Choices a. .05 and .01

b. .01 and .001 c. .001

0.0%

d. All of the above

Score:

4/4

Question 15

(4 points)

The width of a confidence interval will be: Student response: Percent Correct Student Answer Choices Value Response Response 0.0% a. Narrower for 99% confidence than 95% confidence. b. Wider for a sample size of 100 than for a sample size of 50. c. Narrower for 90% confidence than 95% confidence. d. Wider when the sample standard deviation (s) is small than when s is large. e. None of the above

0.0%

100.0%

0.0%

0.0%

Score:

4/4

Question 16

(4 points)

When the null hypothesis is not rejected, there is no possibility of making a Type I error. Student response: Percent Value 100.0% 0.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 17

(4 points)

Everything else being constant, increasing the sample size decreases the probability of committing a Type II error. Student response: Percent Value 100.0% 0.0% Correct Response Student Response Answer Choices a. b. True False

Score:

0/4

Question 18

(4 points)

The production manager for the XYZ manufacturing company is concerned that the customer orders are being shipped late. He asked one of his planners to check the timeliness of shipments for 1,000 orders. The planner randomly selected 1,000 orders and found that 120 orders were shipped late. What is the 95% confidence interval for the proportion of orders shipped late? Student response: Percent Value 0.0% 100.0% 0.0% 0.0% 0.0% Correct Response Student Response Answer Choices a. b. c. d. e. .1031 to .1369 .10 to .14 .09 to .15 .1097 to .1303 .0936 to .1464

Score:

4/4

Question 19

(4 points)

You cannot make a Type II error when the null hypothesis is true. Student response: Percent Value 100.0% 0.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 20

(4 points)

For the following hypothesis test where H0: 10 vs. Ha : > 10, we reject H0 at level of significance and conclude that the true mean is greater than 10 when the true mean is really 8. Based on this information we can state that we have: Student response: Percent Correct Student Answer Choices Value Response Response 100.0% 0.0% 0.0% 0.0% a. Made a Type I error b. Made a Type II error c. Made a correct decision d. Increased the power of the test

Score:

4/4

Question 21

(4 points)

The average customer waiting time at a fast food restaurant has been 7.5 minutes. The customer waiting time has a normal distribution. The manager claims that the use of a new system will decrease average customer waiting time in the store. What is the null and alternative hypothesis for this scenario? Student response: Percent Correct Student Answer Choices Value Response Response 0.0% 0.0% 100.0% 0.0% 0.0% a. H0: = 7.5 and HA 7.5 b. H0: 7.5 and HA> 7.5 c. H0: 7.5 and HA < 7.5 d. H0: > 7.5 and HA 7.5 e. H0: > 7.5 and HA = 7.5

Score:

4/4

Question 22

(4 points)

When conducting a hypothesis test about a single mean, at a given level of significance, as the sample size n increases, the power of the test: Student response: Percent Correct Student Answer Choices Value Response Response 0.0% 100.0% 0.0% 0.0% a. Will decrease. b. Will increase. c. May increase or decrease d. Remains the same

Score:

4/4

Question 23

(4 points)

When the population is normally distributed, population standard deviation is unknown, and the sample size is n = 15; the confidence interval for the population mean is based on: Student response: Percent Correct Student Answer Choices Value Response Response 0.0% 100.0% 0.0% 0.0% 0.0% a. The z (normal) distribution b. The t distribution c. The Binomial distribution d. The Poisson Distribution e. None of the above

Score:

4/4

Question 24

(4 points)

A research and development specialist for a company that produces a certain soft drink wants to determine if a 12-ounce can of a certain brand of soft drink contains 120 calories as the labeling indicates. Using a random sample of 9 cans, the specialist determined that the average calories per can is 124 with a standard deviation of 6 calories. At the .05 level of significance, is there sufficient evidence that the average calorie content of a 12-ounce can is different from 120 calories? Assume that the number of calories per can is normally distributed. Student response: Percent Correct Student Answer Choices Value Response Response 0.0% a. No, t = .667 and .667 is less than the critical value of 2.306. b. No, t = 2 and 2 is less than the critical value of 2.306. c. Yes, t = 2.5 and 2.5 is greater than the critical value of 2.262. d. Yes, t = 2 and 2 is greater than the critical value of 1.833. e. No, t = .667 and .667 is less than the critical value of 2.262.

100.0%

0.0%

0.0%

0.0%

Score:

4/4

Question 25

(4 points)

For the following hypothesis test where H0: 10 vs. Ha : > 10, we reject H0 at level of significance and conclude that the true mean is greater than 10 when the true mean is really 14. Based on this information we can state that we have: Student response: Percent Correct Student Answer Choices Value Response Response 0.0% 0.0% 100.0% 0.0% a. Made a Type I error b. Made a Type II error c. Made a correct decision d. Increased the power of the test

Score:

4/4

4.

6.7.

View Results

9. Final Exam 10.

Question 1

(4 points)

The simple linear regression (least squares method) minimizes: Student response: Percent Value 0.0% 0.0% 0.0% 0.0% 100.0% Correct Student Answer Choices Response Response a. The explained variation b. SSyy c. Total variation d. SSxx e. SSE

Score:

4/4

Question 2

(4 points)

In a simple linear regression model, the coefficient of determination not only indicates the strength of the relationship between independent and dependent variable, but also shows whether the relationship is positive or negative. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

0/4

Question 3

(4 points)

In simple regression analysis the quantity that gives the amount by which Y (dependent variable) changes for a unit change in X (independent variable) is called the Student response: Percent Correct Student Answer Choices Value Response Response 0.0% 100.0% 0.0% 0.0% 0.0% a. Coefficient of determination b. Slope of the regression line c. Y intercept of the regression line d. Correlation coefficient e. Standard error

Score:

4/4

Question 4

(4 points)

Given the following information about a hypothesis test of the difference between two means based on independent random samples, which one of the following is the correct rejection region at a significance level of .05?

Student response: Percent Value 0.0% 0.0% 100.0% 0.0% 0.0%

Correct Response

Student Response

Answer Choices a. Reject H0 if Z > 1.96 b. Reject H0 if Z > 1.645 c. Reject H0 if t > 1.721 d. Reject H0 if t > 2.08 e. Reject H0 if t > 1.782

Score:

0/4

Question 5

(4 points)

When using simple regression analysis, if there is a strong correlation between the independent and dependent variable, then we can conclude that an increase in the value of the independent variable causes an increase in the value of the dependent variable. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

0/4

Question 6

(4 points)

If all data points fell on a straight line, SSE would equal _____ and r would equal _____. Student response: Percent Value 0.0% 0.0% 0.0% 100.0% Correct Response Student Response Answer Choices a. b. c. d. 0,0 1,0 0,1 0, -1 or 1

Score:

4/4

Question 7

(4 points)

There are two types of machines called type A and type B. Both type A and type B can be used to produce a certain product. The production manager wants to compare efficiency of the two machines. He assigns each of the fifteen workers to both types of machines to compare the hourly production rate of the 15 workers. In other words, each worker operates machine A and machine B for one hour each. These two samples are independent. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 8

(4 points)

In a completely randomized ANOVA, other things equal as the sample means get closer to each other, the probability of rejecting the null hypothesis: Student response: Percent Value 100.0% 0.0% 0.0% Correct Response Student Response Answer Choices a. b. c. Decreases Increases Is unaffected.

Score:

0/4

Question 9

(4 points)

The slope of the simple linear regression equation represents the average change in the value of the dependent variable per unit change in the independent variable (X). Student response: Percent Value 100.0% 0.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 10

(4 points)

The correlation coefficient is the ratio of explained variation to total variation. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 11

(4 points)

If we are testing the hypothesis about the mean of a population of paired differences with samples of n1 = 10, n2 = 10, the degrees of freedom for the t statistic is ____. Student response: Percent Value 0.0% 0.0% 100.0% 0.0% 0.0% Correct Response Student Response Answer Choices a. b. c. d. e. 19 18 9 8 10

Score:

0/4

Question 12

(4 points)

Which of the following is a violation of one of the major assumptions of the simple regression model? Student response: Percent Correct Student Answer Choices Value Response Response 0.0% a. The error terms are independent of each other. b. Histogram of the residuals form a bell-shaped, symmetrical curve. c. The error terms occur in a random pattern over time. d. As the value of x increases, the value of the error term also increases.

0.0%

0.0%

100.0%

Score:

4/4

Question 13

(4 points)

For the same value X (independent variable), the confidence interval for the average value of Y (dependent variable) is __________________ the prediction interval for the individual value of Y. Student response: Percent Correct Student Answer Choices Value Response Response 0.0% 100.0% 0.0% a. Larger than b. Smaller than c. Same as

0.0%

d. Sometimes larger than sometimes smaller than

Score:

0/4

Question 14

(4 points)

The correlation coefficient may assume any value between Student response: Percent Value 0.0% 0.0% 0.0% 100.0% 0.0% Correct Response Student Response Answer Choices a. b. and c. d. e. 0 and 8 -1, and 1 -1, and 0 0 and 1

Score:

4/4

Question 15

(4 points)

In an experiment involving matched pairs, a sample of 12 pairs of observations is collected. The degree of freedom for the t statistic is 10. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

0/4

Question 16

(4 points)

The estimated simple linear regression equation minimizes the sum of the squared deviations between each value of Y and the line. Student response: Percent Value 100.0% 0.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 17

(4 points)

When comparing two independent population means, if n1 = 13 and n2 = 10, degrees of freedom for the t statistic is 22. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 18

(4 points)

When using simple linear regression, we would like to use confidence intervals for the _____ and prediction intervals for the _____ at a given value of x. Student response: Percent Correct Student Answer Choices Value Response Response 0.0% 100.0% 0.0% 0.0% a. individual y-value, mean y-value b. Mean y-value, individual y-value c. Slope, mean slope d. y-intercept, mean yintercept

Score:

4/4

Question 19

(4 points)

The point estimate of the variance in a regression model is Student response: Percent Value 0.0% 0.0% 100.0% 0.0% Correct Response Student Response Answer Choices a. b. c. d. SSE b0 MSE b1

Score:

4/4

Question 20

(4 points)

If we are testing the difference between the means of two normally distributed populations with samples of n1 = 10, n2 = 10, the degrees of freedom for the t statistic is ____. Student response: Percent Value 0.0% Correct Response Student Response Answer Choices a. 19

100.0% 0.0% 0.0% 0.0%

b. c. d. e.

18 9 8 20

Score:

4/4

Question 21

(4 points)

In a simple linear regression analysis, the correlation coefficient (a) and the slope (b) _____ have the same sign. Student response: Percent Value 100.0% 0.0% 0.0% Correct Response Student Response Answer Choices a. b. c. always sometimes never

Score:

4/4

Question 22

(4 points)

In testing the difference between the means of two normally distributed populations using large independent random samples, the alternative hypothesis indicates no differences between the two specified means. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 23

(4 points)

When comparing two independent population means by using large samples selected from populations with equal variances, the correct test statistic to use is t. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 24

(4 points)

If r = -1, then we can conclude that there is a perfect relationship between X and Y. Student response: Percent Value 100.0% 0.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 25

(4 points)

The error term is the difference between an individual value of the dependent variable and the corresponding mean value of the dependent variable. Student response: Percent Value 100.0% 0.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

12.13.

View Results

Exam 1 15.

Question 1

(4 points)

Exam1AdditionalTF_q009

The z value tells us the number standard deviations that a value x is from the mean. Student response: Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 2 exam1_q024

(4 points)

A computer system uses 4 bits address size to access all its devices. What is the total number of devices this system can talk to?

Student response: Correct Response

Student Response

Answer Choices a. b. c. d. 4 16 8 32

Score:

4/4


(4 points)

Assume that we have selected a random sample of 25 units from a normally distributed large population. If Q = 15, and W2 = 4, what is the probability that we will obtain a sample mean of less than 14? Student response: Correct Response Student Response Answer Choices a. b. c. d. e. .4938 .0062 .8413 .1587 .3413

Score:

4/4


(4 points)

A random variable is said to be discrete if: Student response: Correct Student Answer Choices Response Response a. Its outcomes are countable b. It can assume any real number within a given interval c. The rules of probability apply d. It can be represented graphically e. All of the above

Score:

4/4

Question 5

(4 points)


A continuous random variable may assume only integer values in a given interval. Student response: Correct Response Student Response Answer Choices a. b. True False

Score:

4/4


(4 points)

Another name(s) for the normal distribution is (are.. Student response: Correct Response Student Response Answer Choices a. b. c. d. e. Bell shaped Gaussian Binomial all of the above both A and B

Score:

4/4


(4 points)

The relationship between the standard normal random variable Z and normal random variable X is that: Student response: Correct Student Answer Choices Response Response a. Only the normal random variable X is continuous. b. Only the standard normal variable Z is continuous. c. The standard normal variable Z counts the number of standard deviations that the value of the normal random variable X is away from its mean. d. The values of the standard normal

random variable Z cannot be negative. e. The values of the normal random variable X cannot be negative.

Score:

4/4

Question 8

(4 points)


The standard deviation of a standard normal distribution is always equal to 1. Student response: Correct Response Student Response Answer Choices a. b. True False

Score:

0/4

Question 9

(4 points)

Exam1Addtional_q005

The Eastern State University law school ranks graduating students based on their cumulative GPA and assigns a normal z score to each student. Regina Monson just completed all of the requirements for her law degree and her z score is 1.34. Based on her z score, we can conclude that she is in the upper _____ of her graduating class: Student response: Correct Response Student Response Answer Choices a. b. c. d. e. 10% 20% 50% 30% 40%

Score:

0/4

Question 10

(4 points)


The mean of the sampling distribution of Student response: Correct

is always equal to the mean of the sampled population. Answer Choices

Student

Response

Response a. b. True False

Score:

4/4

Question 11

(4 points)


The mean of a standard normal distribution is always equal to 1. Student response: Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 12

(4 points)


A continuous probability distribution having a rectangular shape where the probability is evenly distributed over an interval of numbers is called a uniform probability distribution. Student response: Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 13

(4 points)

Exam1Addtional_q009

Assume that we have selected a random sample of 25 units from a normally distributed large population. If = 15, and2

= 4, what is the standard deviation of the sampling distribution of Student Response Answer Choices a. b. c. 15 4 2

?


d. e.

1 .4

Score:

0/4


(4 points)

If the sampled population has a mean 48 and standard deviation 16, then the mean and the standard deviation for the sampling distribution of Student response: Correct Response Student Response for n = 16 are: Answer Choices a. b. c. d. e. 4 and 1 12 and 4 48 and 4 48 and 1 48 and 16

Score:

4/4

Question 15

(4 points)


The normal probability distribution is a discrete probability distribution. Student response: Correct Response Student Response Answer Choices a. b. True False

Score:

0/4

Question 16

(4 points)

Exam1Addtional_q008

If a population distribution is known to be normal, then it follows that: Student response: Correct Student Answer Choices Response Response a. the sample mean must equal the population mean.

b. the sample mean must equal the population mean for large samples. c. the sample standard deviation must equal the population standard deviation. d. All of the above. e. None of the above.

Score:

0/4


(4 points)

Which of the following is a valid probability value for a discrete random variable? Student response: Correct Response Student Response Answer Choices a. b. c. d. .2 1.01 -.7 All of the above

Score:

4/4


(4 points)

Which of the following statements is not a property of the normal probability distribution? Student response: Correct Student Answer Choices Response Response a. The normal distribution is symmetric. b. 95.44% of all possible observed values of the random variable x are within plus or minus three standard deviations of the population mean. c. The mean, median, and mode are equal. d. The area under the normal curve to the right of the mean is equal to the area under the normal curve to the left of the mean.

Score:

4/4

Question 19

(4 points)

Exam1Addtional_q001

The area under the normal curve between z = 0 and z = 1 is ________________ the area under the normal curve between z =1 and z = 2. Student response: Correct Student Answer Choices Response Response a. Less than b. Greater than c. Equal to d. A, B, or C above dependent on the value of the mean e. A, B, or C above dependent on the value of the standard deviation

Score:

4/4


(4 points)

If the random variable of x is normally distributed, 68.26% of all possible observed values of x will be within two standard deviations of the mean. Student response: Correct Response Student Response Answer Choices a. b. True Fasle

Score:

4/4

Question 21

(4 points)

Exam1Addtional_q004

If the random variable of x is normally distributed, ____% of all possible observed values of x will be within three standard deviations of the mean. Student response: Correct Response Student Response Answer Choices a. b. c. 68.26 95.44 99.73

d. e.

100 None of the above

Score:

4/4

Question 22

(4 points)


The Central Limit Theorem states that as the sample size increases, the population distribution more closely approximates a normal distribution Student response: Correct Response Student Response Answer Choices a. b. True False

Score:

0/4


(4 points)

The normal approximation of the binomial distribution is appropriate when: Student response: Correct Response Student Response Answer Choices a. b. c. d. e. np u 5 n(1 - p) u 5 np e 5 n(1 - p) e 5 and np e 5 np u 5 and n(1 - p) u 5

Score:

4/4

Question 24

(4 points)


The sampling distribution of the sample mean is developed by repeatedly taking samples of size n and computing the sample means and reporting the resulting sample means in the form of a probability distribution. Student response: Correct Response Student Response Answer Choices a. True

b.

False

Score:

4/4

Question 25

(4 points)


The standard deviation of the sampling distribution of the sample mean is . Student response: Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 26

(4 points)


If a population is known to be normally distributed, then it follows that the sample standard deviation must equal ? Student response: Correct Response Student Response Answer Choices a. b. True False

Score:

0/4


(4 points)

The standard deviation of all possible sample proportions increases as the sample size increases. Student response: Correct Response Student Response Answer Choices a. b. True Fasle

Score:

4/4

Question 28

(4 points)


In a statistical study, the random variable X = 1, if the house is colonial, and X = 0 if the house is not colonial, then it can be stated that the random variable is continuous. Student response: Correct Response Student Response Answer Choices a. b. True False

Score:

4/4


(4 points)

The College of Business Administration at Acorn University offers a major in Finance. Based on historical records, 30% of the College of Business students major in Finance. A random sample of 20 students is selected. What are the mean and the standard deviation of this distribution? Student response: Correct Response Student Response Answer Choices a. b. c. d. e. .3 and 2.44 3 and 4.2 6 and 4.2 6 and 2.05 20 and 2.05

Score:

4/4


(4 points)

For a binomial probability experiment, with n = 150 and p = .2, it is appropriate to use the normal approximation to the binomial distribution. Student response: Correct Response Student Response Answer Choices a. b. True Fasle

Score:

4/4

Question 31

(4 points)

Exam1Addtional_q002

The price-to-earning ratio for firms in a given industry is distributed according to normal distribution. In this industry, a firm with a standard normal variable value of Z = 1: Student response: Correct Student Answer Choices Response Response a. Has an above average price-toearning ratio. b. Has a below average price-toearnings ratio. c. Has an average price-to-earnings ratio. d. May have an above average or below average price-to-earnings ratio.

Score:

0/4


(4 points)

All continuous random variables are normally distributed. Student response: Correct Response Student Response Answer Choices a. b. True Fasle

Score:

4/4

Question 33

(4 points)

Exam1Addtional_q006

As the sample size ______________ the variation of the sampling distribution of _____________. Student response: Correct Response Student Response Answer Choices a. Decreases, decreases b. Increases, remains the same c. Decreases, remains the same d. Increases, decreases e. None of the above

Score:

4/4


(4 points)

The MPG (Miles per Gallon) for a mid-size car is normally distributed with a mean of 32 and a standard deviation of .8. What is the probability that the MPG for a selected mid-size car would be Less than 33.2? Student response: Correct Response Student Response Answer Choices a. b. c. d. e. 43.32% 6.68% 93.32% 86.64% 13.36%

Score:

0/4


(4 points)

The College of Business Administration at Acorn University offers a major in Finance. Based on historical records, 30% of the College of Business students major in Finance. A random sample of 20 students is selected. What is the probability that exactly 3 of the selected students are majoring in Finance? Student response: Correct Response Student Response Answer Choices a. b. c. d. e. .0716 .027 .09 .107 .0354

Score:

4/4


(4 points)

A student's grade on an examination was transformed to a z value which is negative. Therefore, we know that he scored:


Student Response

Answer Choices a. Higher than 16% of the class b. Higher than 45% of the class c. Above the first quartile d. Below the mean e. Lower than 16% of the class

Score:

4/4

Question 37

(4 points)


If the sampled population is exactly normal distribution, then the sampling distribution of expected to be normal regardless of the sample size. Student response: Correct Response Student Response Answer Choices a. b. True False

is also

Score:

0/4


(4 points)

A standard normal distribution has a mean of _____ and standard deviation of _____. Student response: Correct Response Student Response Answer Choices a. b. c. d. zero, zero zero, one one, one one, zero

Score:

4/4


(4 points)

The mean life of pair of shoes is 40 months with a standard deviation of 8 months. If the life of the

shoes is normally distributed, how many pairs of shoes out of one million will need replacement before 36 months? Student response: Correct Response Student Response Answer Choices a. b. c. d. 500,000 808,500 191,500 308,500

Score:

4/4

Question 40

(4 points)


As the sample size increases, the standard deviation of the sampling distribution increases. Student response: Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 41

(4 points)


The sampling distribution of 1. Student response: Correct Response

must be a normal distribution with a mean 0 and standard deviation Student Response Answer Choices a. b. True False

Score:

0/4

Question 42

(4 points)

Exam1Addtional_q007

Consider a sampling distribution formed based on n = 3. The standard deviation of the population of all sample means x is ______________less than the standard deviation of the population of individual measurements .


Student Response

Answer Choices a. b. c. Always Sometimes Never

Score:

4/4

Question 43

(4 points)


Two normally distributed variables can have equal means and unequal standard deviations. Student response: Correct Response Student Response Answer Choices a. b. True False

Score:

0/4


(4 points)

The _____________distribution would most likely be used to describe the distribution of time between arrivals of customers at the grocery store. Student response: Correct Response Student Response Answer Choices a. b. c. d. e. Normal Exponential Poisson Binomial Uniform

Score:

4/4


(4 points)

If the random variable X has a mean of Q and a standard deviation W, then (X - Q)/W has a mean and standard deviation respectively:


Student Response

Answer Choices a. b. c. d. Q and W and s 1 and 0 0 and 1

Score:

0/4


(4 points)

A newly married couple plans to have four children. Suppose that boys and girls are equally likely each time a child is born. What is the probability the couple will have no more than 2 boys? Student response: Correct Response Student Response Answer Choices a. b. c. d. 25% 37.5% 62.5% 50%

Score:

4/4

Question 47

(4 points)


The exponential probability distribution is based on a continuous random variable. Student response: Correct Response Student Response Answer Choices a. b. True False

Score:

4/4


(4 points)

The actual weight of hamburger patties is an example of a continuous random variable. Student response: Correct Student Answer Choices

Response

Response a. b. True Fasle

Score:

4/4

Question 49

(4 points)

Exam1Addtional_q003

A student's grade on an examination was transformed to a z value which is negative. Therefore, we know that he scored: Student response: Correct Response Student Response Answer Choices a. Higher than 16% of the class b. Higher than 45% of the class c. Above the first quartile d. Below the mean e. Lower than 16% of the class

Score:

4/4

Question 50

(4 points)


The mean and median are the same for a normal distribution. Student response: Correct Response Student Response Answer Choices a. b. True False

Score:

4/4


(4 points)

The number of defective pencils in a lot of 1000 is an example of a continuous random variable. Student response: Correct Response Student Response Answer Choices a. True

b.

Fasle

Score:

4/4

Total score: 16.

152 / 204 = 74.5%

18.Question 1 (4 points) In testing the difference between the means of two normally distributed populations using large independent random samples, the alternative hypothesis indicates no differences between the two specified means. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 2

(4 points)

In a completely randomized ANOVA, other things equal as the sample means get closer to each other, the probability of rejecting the null hypothesis: Student response: Percent Value 100.0% 0.0% 0.0% Correct Response Student Response Answer Choices a. b. c. Decreases Increases Is unaffected.

Score:

4/4

Question 3

(4 points)

The point estimate of the variance in a regression model is Student response: Percent Value 0.0% 0.0% 100.0% 0.0% Correct Response Student Response Answer Choices a. b. c. d. SSE b0 MSE b1

Score:

4/4

Question 4

(4 points)

When using simple linear regression, we would like to use confidence intervals for the _____ and prediction intervals for the _____ at a given value of x. Student response: Percent Correct Student Answer Choices Value Response Response 0.0% 100.0% 0.0% 0.0% a. individual y-value, mean y-value b. Mean y-value, individual y-value c. Slope, mean slope d. y-intercept, mean yintercept

Score:

4/4

Question 5

(4 points)

The correlation coefficient is the ratio of explained variation to total variation. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 6

(4 points)

In a simple linear regression analysis, the correlation coefficient (a) and the slope (b) _____ have the same sign. Student response: Percent Value 100.0% 0.0% 0.0% Correct Response Student Response Answer Choices a. b. c. always sometimes never

Score:

4/4

Question 7

(4 points)

There are two types of machines called type A and type B. Both type A and type B can be used to produce a certain product. The production manager wants to compare efficiency of the two machines. He assigns each of the fifteen workers to both types of machines to compare the hourly

production rate of the 15 workers. In other words, each worker operates machine A and machine B for one hour each. These two samples are independent. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

0/4

Question 8

(4 points)

If r = -1, then we can conclude that there is a perfect relationship between X and Y. Student response: Percent Value 100.0% 0.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 9

(4 points)

In a simple linear regression model, the coefficient of determination not only indicates the strength of the relationship between independent and dependent variable, but also shows whether the relationship is positive or negative. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 10

(4 points)

For the same value X (independent variable), the confidence interval for the average value of Y (dependent variable) is __________________ the prediction interval for the individual value of Y. Student response: Percent Correct Student Answer Choices Value Response Response 0.0% 100.0% 0.0% 0.0% a. Larger than b. Smaller than c. Same as d. Sometimes larger than sometimes smaller than

Score:

0/4

Question 11

(4 points)

Given the following information about a hypothesis test of the difference between two means based on independent random samples, which one of the following is the correct rejection region at a significance level of .05?

Student response:

Percent Correct Student Answer Choices Value Response Response 0.0% 0.0% 100.0% 0.0% 0.0% a. Reject H0 if Z > 1.96 b. Reject H0 if Z > 1.645 c. Reject H0 if t > 1.721 d. Reject H0 if t > 2.08 e. Reject H0 if t > 1.782

Score:

0/4

Question 12

(4 points)

The simple linear regression (least squares method) minimizes: Student response: Percent Correct Student Answer Choices Value Response Response 0.0% 0.0% 0.0% 0.0% 100.0% a. The explained variation b. SSyy c. Total variation d. SSxx e. SSE

Score:

4/4

Question 13

(4 points)

If we are testing the difference between the means of two normally distributed populations with samples of n1 = 10, n2 = 10, the degrees of freedom for the t statistic is ____. Student response: Percent Value 0.0% 100.0% 0.0% 0.0% 0.0% Correct Response Student Response Answer Choices a. b. c. d. e. 19 18 9 8 20

Score:

4/4

Question 14

(4 points)

When comparing two independent population means, if n1 = 13 and n2 = 10, degrees of freedom for the t statistic is 22. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 15

(4 points)

The error term is the difference between an individual value of the dependent variable and the corresponding mean value of the dependent variable. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

0/4

Question 16

(4 points)

If all data points fell on a straight line, SSE would equal _____ and r would equal _____. Student response: Percent Value 0.0% 0.0% 0.0% 100.0% Correct Response Student Response Answer Choices a. b. c. d. 0,0 1,0 0,1 0, -1 or 1

Score:

4/4

Question 17

(4 points)

If we are testing the hypothesis about the mean of a population of paired differences with samples of n1 = 10, n2 = 10, the degrees of freedom for the t statistic is ____. Student response: Percent Value Correct Response Student Response Answer Choices

0.0% 0.0% 100.0% 0.0% 0.0%

a. b. c. d. e.

19 18 9 8 10

Score:

4/4

Question 18

(4 points)

In an experiment involving matched pairs, a sample of 12 pairs of observations is collected. The degree of freedom for the t statistic is 10. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 19

(4 points)

Which of the following is a violation of one of the major assumptions of the simple regression model? Student response: Percent Correct Student Answer Choices Value Response Response 0.0% a. The error terms are independent of each other. b. Histogram of the residuals form a bellshaped, symmetrical curve. c. The error terms occur in a random pattern over time. d. As the value of x increases, the value of the error term also increases.

0.0%

0.0%

100.0%

Score:

0/4

Question 20

(4 points)

The estimated simple linear regression equation minimizes the sum of the squared deviations between each value of Y and the line.

Student response:

Percent Value 100.0% 0.0%

Correct Response

Student Response

Answer Choices a. b. True False

Score:

0/4

Question 21

(4 points)

When comparing two independent population means by using large samples selected from populations with equal variances, the correct test statistic to use is t. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 22

(4 points)

In simple regression analysis the quantity that gives the amount by which Y (dependent variable) changes for a unit change in X (independent variable) is called the Student response: Percent Correct Student Answer Choices Value Response Response 0.0% 100.0% 0.0% 0.0% 0.0% a. Coefficient of determination b. Slope of the regression line c. Y intercept of the regression line d. Correlation coefficient e. Standard error

Score:

4/4

Question 23

(4 points)

The correlation coefficient may assume any value between Student response: Percent Value 0.0% 0.0% 0.0% Correct Response Student Response Answer Choices a. b. and c. 0 and 8 0 and 1

100.0% 0.0%

d. e.

-1, and 1 -1, and 0

Score:

4/4

Question 24

(4 points)

The slope of the simple linear regression equation represents the average change in the value of the dependent variable per unit change in the independent variable (X). Student response: Percent Value 100.0% 0.0% Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 25

(4 points)

When using simple regression analysis, if there is a strong correlation between the independent and dependent variable, then we can conclude that an increase in the value of the independent variable causes an increase in the value of the dependent variable. Student response: Percent Value 0.0% 100.0% Correct Response Student Response Answer Choices a. b. True False

19. 20. If the random variable X has a mean on and a standard deviation of , then [(X )/ ] has a mean and standard deviation respectively: a. and b. and s c. 1 and 0 d. 0 and 1 21. Which of the following statements is not a property of the normal probability distribution? a. The normal distribution is symmetric. b. 95.44% of all possible observed values of the random variable x are within plus or minus three standard deviations of the population mean. c. The mean, median and mode are equal. d. The area under the normal curve to the right of the mean is equal to the area under the normal curve to the left of the mean. 22. The College of Business Administration at Acorn University offers a major in Finance. Based on historical records, 30% of the College of Business students

major in Finance. A random sample of 20 students is selected. What is the probability that exactly 3 of the selected students are majoring in Finance? a. .0716 b. .027 c. .09 d. .107 e. .0354 23. Another name(s) for the normal distribution is (are) a. Bell shaped b. Gaussian c. Binomial d. All of the above e. Both A and B 24. The area under the normal curve between z = 0 and z = 1 is ________ the area under the normal curve between z = 1 and z = 2. a. Less than b. Greater than c. Equal to d. A, B, or C above dependent on the value of the mean. e. A, B, or C above dependent on the value of the standard deviation 25. Assume that we have selected a random sample of 25 units from a normally distributed large population. If = 15, and 2 = 4, what is the probability that we will obtain a sample mean of less than 14? a. .4938 b. .0062 c. .8413 d. .1587 e. .3413 26. A random variable is said to be discrete if: a. Its outcomes are countable. b. It can assume any real number within a given interval. c. The rules of probability apply. d. It can be represented graphically. e. All of the above. 27. The sampling distribution of the sample mean is developed by repeatedly taking samples of size n and computing the sample means and reporting the resulting sample means in the form of a probability distribution. a. True b. False 28. A computer system uses 4 bits address size to access all its devices. What is the total number of devices this system can talk to? a. 4 b. 16 c. 8 d. 32

29. The MPG (Miles per Gallon) for a mid-size car is normally distributed with a mean of 32 and a standard deviation of .8. What is the probability that the MPG for a selected mid-size car would be less than 33.2? a. 43.32% b. 6.68% c. 93.32% d. 86.64% e. 13.36% 30. The standard deviation of all possible sample proportions increases as the sample size increases. a. True b. False 31. A newly married couple plans to have four children. Suppose that boys and girls are equally likely each time a child is born. What is the probability the couple will have no more than 2 boys? a. 25% b. 37.5% c. 62.5% d. 50% 32. The mean of a standard normal distribution is always equal to 1. a. True b. False 33. The sampling distribution of must be a normal distribution with a mean 0 and standard deviation 1. a. True b. False 34. A standard normal distribution has a mean of ______ and standard deviation of _____. a. zero, zero b. zero, one c. one, one d. one, zero 35. The z value tells us the number standard deviations that a value x is from the mean. a. True b. False 36. In a statistical study, the random variable x = 1, if the house is colonial, and x = 0 if the house is not colonial, then it can be stated that the random variable is continuous. a. True b. False 37. All continuous random variables are normally distributed. a. True b. False 38. If the sampled population has a mean 48 and standard deviation 16, then the mean and the standard deviation for the sampling distribution of for n = 16 are:

a. 4 and 1 b. 12 and 4 c. 48 and 4 d. 48 and 1 e. 48 and 16 39. A continuous probability distribution having a rectangular shape where the probability is evenly distributed over an interval of numbers is called a uniform probability distribution. a. True b. False 40. The normal approximation of the binomial distribution is appropriate when: a. np 5 b. n(1 p) 5 c. np 5 d. n(1 p) 5 and np 5 e. np 5 and n(1 p) 5 41. The exponential probability distribution is based on a continuous random variable. a. True b. False 42. The standard deviation of the sampling distribution of the sample mean is . a. True b. False 43. As the sample size increases, the standard deviation of the sampling distribution increases. a. True b. False 44. The mean of the sampling distribution of is always equal to the mean of the sampled population. a. True b. False 45. The power of a statistical test is the probability of rejecting the null hypothesis when it is true. a. True b. False 46. A research and development specialist for a company that produces a certain soft drink wants to determine if a 12-ounce can of a certain brand of soft drink contains 120 calories and the labeling indicates. Using a random sample of 9 cans, the specialist determined that the average calories per can is 124 with a standard deviation of 6 calories. At the .05 level of significance, is there sufficient evidence that the average calorie content of a 12-ounce can is different from 120 calories? Assume that the number of calories per can is normally distributed. a. No, t = .667 and .667 is less than the critical value of 2.306. b. No, t = 2 and 2 is less than the critical value of 2.306 c. Yes, t = 2.5 and 2.5 is greater than the critical value of 2.262 d. Yes, t = 2 and 2 is greater than the critical value of 1.833

e. No, t = .667 and .667 is less than the critical value of 2.262 47. When the null hypothesis is true, there is not possibility of making a type I error. a. True b. False 48. What value(s) of alpha would we reject Ho for greater than the mean 10 if = 11, s = 2, and n = 36? a. .05 and .01 b. .01 and .001 c. .001 d. All of the above 49. The average customer waiting time at a fast food restaurant has been 7.5 minutes. The customer waiting time has a normal distribution. The manager claims that the use of a new system will decrease average customer waiting time in the store. What is the null and alternative hypothesis for this scenario? a. H0: =7.5 and H 7.5 b. H0: 7.5 and H > 7.5 c. H0: 7.5 and H < 7.5 d. H0: > 7.5 and H 7.5 e. H0: >7.5 and H =7.5 50. For a given hypothesis test, if we do not reject H0, and H0 is true. a. No error has been committed. b. Type I error has been committed. c. Type II error has been committed. d. Type III error has been committed 51. When conducting a hypothesis test about a single mean, at a given level of significance, as the sample size n increases, the power of the test: a. Will decrease. b. Will increase. c. May increase or decrease. d. Remains the same. 52. When the null hypothesis is not rejected, there is no possibility of making a Type I error. a. True b. False 53. For the following hypothesis test where H0: 10 vs. H : > 10, we reject H0 at level of significance and conclude that the true mean is greater than 10 when the true mean is really 14. Based on this information we can state that we have: a. Made a Type I error. b. Made a Type II error. c. Made a correct decision. d. Increased the power of the test. 54. If a null hypothesis is rejected at a significance level of 0.01, it will _____ be rejected at a significance level of 0.05. a. Always b. Sometimes c. Never

55. You cannot make a Type II error when the null hypothesis is true. a. True b. False 56. Alpha ( ) is the probability that the test statistic would assume a value as or more extreme than the observed value of the test. a. True b. False 57. When determining the sample size, if the value found is not an integer initially, the next highest integer value will _______ be chosen. a. Always b. Sometimes c. Never 58. In a manufacturing process a random sample of 9 bolts manufactured has a mean length of 3 inches with a standard deviation of 3 inches with a standard deviation of .3 inches. What is the 95% confidence interval for the true mean length of the bolt? a. 2.804 to 3.196 b. 2.308 to 3.692 c. 2.770 to 3.231 d. 2.412 to 3.588 59. A financial analyst believes that a fast food chain should be purchased if average daily profits are more than $1,000 per day. The standard deviation of daily profits is known to $200 and the significance level is .05. A random sample of 100 days resulted in an average profit of $1050. At the .05 level of significance, there is not sufficient evidence that the average daily profit is more than $1,000 per day. a. True b. False 60. The following list represents a sample of the ages of the soldiers enlisting in the military: 19, 22, 23, 19, 21, 22, 19, 23, 21. Assume that the population standard deviation is known to be 2 years. Construct a 99% confidence interval for the average age of the soldier enlisting in the military. a. 17.92 to 24.08 b. 15.85 to 26.15 c. 18.76 to 23.24 d. 19.28 to 22.72 e. 19.42 to 22.58 61. In a manufacturing process, we are interested in measuring the average length of a certain type of bolt. Past data indicates that the standard deviation is .25 inches. How many bolts should be sampled in order to make us 95% confident that the sample mean bolt length is within .02 inches of the true mean bolt length? a. 25 b. 49 c. 423 d. 601 e. 1225 62. A statistical quality control process for cereal production measures the weight of a cereal box. The population standard deviation is known to be .06 ounces. In order to

achieve a 97% confidence with a margin of error of .02 ounces, how large a sample should be used? a. 43 b. 707 c. 32 d. 25 e. 20 63. The t distribution approaches the ______ as the sample size ________. a. Binomial, increases. b. Binomial, decreases. c. Z, decreases. d. Z, increases. 64. According to a recent major survey, 70% of the respondents indicated that there is too much violence on TV. For a random sample of 40 people, what is the 95% confidence interval of the proportion of people who feel that there is too much violence on TV? a. .70 .12 b. .70 .03 c. .70 .90 d. .70 .14 e. .70 .07 65. The average waiting time per customer at a fast food restaurant has been 7.5 minutes. The customer waiting time has a normal distribution. The manager claims that the use of a new cashier system will decrease the average customer waiting time in the store. Based on a random sample of 16 customer transactions the mean waiting time is 6.3 minutes and the standard deviation is 2 minutes per customer. What is the value of the test statistic? a. t = -1.2 b. t = 2.4 c. t = -2.4 d. t = -0.6 e. t = 9.6 66. When the null hypothesis is true, there is no possibility of making a Type I error. a. True b. False 67. If a one-sided null hypothesis for a single mean cannot be rejected at a given significance level, then the corresponding two-sided null hypothesis (i.e., the same sample size, the same standard deviation, and the same mean) will _________ be rejected at the same significance level. a. Always b. Sometimes c. Never 68. For the following hypothesis test where H0: 10 vs. H : > 10, we reject H0 at level of significance ? and conclude that the true mean is greater than 10 when the true mean is really 8. Based on this information we can state that we have: a. Made a Type I error.

b. Made a Type II error. c. Made a correct decision. d. Increased the power of the test. 69. When conducting a hypothesis test about a single mean, other relevant factors held constant, increasing the level of significance from .05 to .10 will reduce the probability of a Type I error. a. True b. False 70. In testing the difference between the means of two normally distributed populations using large independent random samples, the alternative hypothesis indicates no differences between the two specified means. a. True b. False 71. In a completely randomized ANOVA, other things equal as the sample means get closer to each other, the probability of rejecting the null hypothesis: a. Decreases b. Increases c. Is unaffected 72. The point estimate of the variance in a regression model is a. SSE b. b0 c. MSE d. b1 73. When using simple linear regression, we would like to use confidence intervals for the ________ and prediction intervals for the ________ at a given value of x. a. Individual y-value, mean y-value b. Mean y-value, individual y-value c. Slope, mean slope d. Y-intercept, mean y-intercept 74. The correlation coefficient is the ratio of explained variation to total variation. a. True b. False 75. In a simple linear regression analysis, the correlation coefficient (a) and the slope (b) ________ have the same sign. a. Always b. Sometimes c. Never 76. There are two types of machines called type A and type B. Both type A and type B can be used to produce a certain product. The production manager wants to compare efficiency of the two machines. He assigns each of the fifteen workers to both types of machines to compare the hourly production rate of the 15 workers. In other words, each worker operates machine A and machine B for one hour each. These two samples are independent. a. True b. False

77. If r = - 1, then we can conclude that there is a perfect relationship between X and Y. a. True b. False 78. In a simple linear regression model, the coefficient of determination not only indicates the strength of the relationship between independent and dependent variable, but also shows whether the relationship is positive or negative. a. True b. False 79. For the same value X (independent variable), the confidence interval for the average value of Y (dependent variable) is ________ the prediction interval for the individual value of Y. a. Larger than b. Smaller than c. Same as d. Sometimes larger than sometimes smaller than 80. Given the following information about a hypothesis test of the difference between two means based on independent random samples, which one of the following is the correct rejection region at a significance level of .05? a. Reject H0 if Z > 1.96 b. Reject H0 if Z > 1.645 c. Reject H0 if t > 1.721 d. Reject H0 if t > 2.08 e. Reject H0 if t > 1.782 81. The simple linear regression (least squares method) minimizes: a. The explained variation b. SSyy c. Total variation d. SSxx e. SSE 82. If we are testing the difference between the means of two normally distributed populations with samples of n1 = 10, n2 = 10, the degrees of freedom for the test statistic is ________. a. 19 b. 18 c. 9 d. 8 e. 20 83. When comparing two independent population means, if n1 = 13 and n2 = 10, degrees of freedom for the t statistic is 22. a. True b. False 84. The error term is the difference between an individual value of the dependent variable and the corresponding mean value of the dependent variable.

a. True b. False 85. If all the data points fell on a straight line, SSE would equal ________ and r would equal ________. a. 0,0 b. 1,0 c. 0,1 d. 0, -1 or 1 86. If we are testing the hypothesis about the mean of a population of paired differences with samples of n1 = 10, n2 = 10, the degrees of freedom for the t statistic is ________. a. 19 b. 18 c. 9 d. 8 e. 10 87. In an experiment involving matched pairs, a sample of 12 pairs of observations is collected. The degree of freedom for the t statistic is 10. a. True b. False 88. Which of the following is a violation of one of the major assumptions of the simple regression model? a. The error terms are independent of each other. b. Histogram of the residuals form a bell-shaped, symmetrical curve. c. The error terms occur in a random pattern over time. d. As the value of x increases, the value of the error term also increases. 89. The estimated simple linear regression equation minimizes the sum of the standard deviations between each value of Y and the line. a. True b. False 90. When comparing two independent population means by using large samples selected from populations with equal variances, the correct test statistic to use is t. a. True b. False 91. In simple regression analysis the quantity that gives the amount by which Y (dependent variable) changes for a unit change in X (independent variable) is called the a. Coefficient of determination b. Slope of the regression line c. Y intercept of the regression line d. Correlation coefficient e. Standard error 92. The correlation coefficient may assume any value between a. 0 and 1 b. - and c. 0 and 8

d. -1, and 1 e. -1, and 0 93. The slope of the simple linear regression equation represents the average change in the value of the dependent variable per unit change in the independent variable (X). a. True b. False 94. When using simple regression analysis, if there is a strong correlation between the independent and dependent variable, then we can conclude that an increase in the value of the independent variable causes an increase in the value of the dependent variable. a. True b. FalseA financial analyst believes that a fast food chain should be purchased if average daily profits are more than $1,000 per day. The standard deviation of daily profits is known to be $200 and the significance level is .05. A random sample of 100 days resulted in an average profit of $1050. At the .05 level of signifance, there is not sufficient evidence that the average daily profit is more than $1000 per day. *FALSE* When the level of confidence and sample standard deviation remain the same, a confidence interval for a population mean based on a sample of N=100 will be narrower than a confidence interval for a population mean based on a sample of n=50. *TRUE* Which statement is incorrect? The null hyp. contains the equality sign. (true) When a false null hyp. is not rejected, a Type II error has occurred. (true) If a null hyp. is rejected, it is conducted that the alternative hypothesis is true. (true) If we fail to reject the null hyp., then it is proven that the null hyp. is true *FALSE* In a manufacturing process, we are interested in measuring the average length of a certain type of bolt. Past data indicates that the standard deviation is .25 inches. How many bolts should be sampled in order to make us 95% confident that the sample mean bolt length is within .02 inches of the true mean bolt length? *601* For the following hypothesis test where Ho: 10, we reject Ho at level of significance ? and conclude that the true mean is greater than 10 when the true mean is really 8. Based on this information we can state that we have: *MADE A TYPE I ERROR* The power of a statistical test is the probability of rejecting the null hypothesis when it is true. *FALSE* You cannot make a Type II Error when the null hypothesis is true. *TRUE* The average waiting time per customer at a fast food restaurant has been 7.5 minutes. The customer waiting time has a normal distribution. The manager claims that the use of a new cashier system will decrease the average customer waiting time in the store. Based on a random sample of 16 customer transactions the mean waiting time is 6.3 minutes and the standard deviation is 2 minutes per customer. What is the value of the test statistic?

*t = -2.4* If a 1-sided null hyp. for a single mean cannot be rejected at a given significance level, then the corresponding 2-sided null hyp. (i.e., the same sample size, the same standard deviation, and the same mean) will _________ be rejected at the same significance level. *NEVER* A Confidence interval increases in width as: The level of confidence increases n decreases s increases *ALL OF THE ABOVE* When the level of confidence and sample standard deviation remain the same, a confidence interval for a population mean based on a sample of n = 100 will be ___________ a confidence interval for a population mean based on a sample of n = 50. *NARROWER THAN* When determining the sample size, if the value found is not an integer initially, then next highest integer value will __________ be chosen. *ALWAYS* If a 2-sided null hyp. is rejected for a single mean at a given significance level, the corresponding 1-sided null hyp. (ie, the same sample size, the same standard deviation, and the same mean) will __________ be rejected at the same significance level. *ALWAYS* The t distribution approaches the __________ as the sample size __________. *Z, INCREASES* The width of a confidence interval will be: *NARROWER FOR 90% CONFIDENCE THAN 95% CONFIDENCE* What sample size would be required to estimate mu to within +/- 3 with 95% confidence if the population standard deviation is 24.5? *257* A test statistic is computed from sample data in hyp. testing and is used in making a decision about whether or not to reject the null hyp. *TRUE* According to a recent major survey, 70% of the respondents indicated that there is too much violence on TV. For a random sample of 40 people, what is the 95% confidence interval of the proportion of people who feel that there is too much violence on TV? *.70 +/- .14* A statistical quality control process for cereal production measures the weight of a cereal box. The population standard deviation is known to be .06 ounces. In order to achieve a 97% confidence with a margin of error of.02 ounces, how large a sample should be used? *43* In a manufacturing process a random sample of 9 bolts manufactured has a mean length of 3 inches with a variance of .09. What is the 90% confidence interval for the true mean length of the bolt? *2.8140 to 3.8160* or *2.8140 to 3.1860*

The average customer waiting time at a fast food restaurant has been 7.5 minutes. The customer waiting time has a normal distribution. The manager claims that the use of a new system will decrease average customer waiting time in the store. What is the null and alternative hyp. for this scenario? *Ho: mu >_ 7.5 and Ha < 7.5* What value(s) of alpha would we reject Ho for mu greater than the mean of 10 if =11, s = 2, and n = 36? *.05 and .01* A plant quality control manager wishes to estimate the strength of a cable wire. A random sample of 61 wires is tested. The strength of the cable wire is measured in pounds per square inch. Based on the sample results, the sample mean is 238.4 pounds and the sample standard deviation is 35 pounds. What is the 98% confidence interval? *227.96 to 248.84* If a null hyp. is rejected at a significance level of 0.01, it will __________ be rejected at a significance level of 0.05. *ALWAYS* As the level of significance a increases, we are more likely to reject the null hyp. *TRUE* A test statistic is computed from sample data in hyp. testing and is used in making a decision about whether or not to reject the null hyp. *TRUE* The null hypothesis always includes an equal (=) sign. *TRUE* When the null hypothesis is not rejected, there is no possibility of making a Type I error. *TRUE* A research and development specialist for a company that produces a certain soft drink wants to determine if a 12-ounce can of a certain brand of soft drink contains 120 calories as the labeling indicates. Using a random sample of 9 cans, the specialist determined that the average calories per can is 124 with a standard deviation of 6 calories. At the .05 level of significance, is there sufficient evidence that the average calorie content of a 12-ounce can is different from 120 calories? Assume that the number of calories per can is normally distributed. *NO, t = 2 AND 2 IS LESS THAN THE CRITICAL VALUE OF 2.306* The power of a statistical test is the probability of rejecting the null hypothesis when it is true *FALSE* When the null hypothesis is true, there is no possibility of making a Type I error. *FALSE* When the population is normally distributed, population standard deviation (o~) is unknown, and the sample size is n = 15; the confidence interval for the population mean is mu based on: *THE t DISTIRBUTION* Determine the 99% confidence interval for the true population mean, if a random sample size 16 has a sample mean of 46.8 pounds and standard deviation of 4 pounds. *43.85 TO 49.78* For a given hypothesis test, if we do not reject Ho, and Ho is true. *NO ERROR HAS BEEN COMMITED.*

For the following hypothesis test where Ho: U 10, we reject Ho at level of significance o and conclude that the true mean is greater than 10 when the true mean is really 14. Based on this information we can state that we have: *MADE A CORRECT DECISION* In a manufacturing process a random sample of 9 bolts manufactured has a mean length of 3 inches with a standard deviation of .3 inches. What is the 95% confidence interval for the true mean length of the bolt? *2.770 TO 3.231* Type II error is defined as the probability of _____ Ho, when it should __________. *FAILING TO REJECT; BE REJECTED* The null hyp. is a statement that will be accepted only if there is convincing sample evidence that it is true. *FALSE* Confidence intervals can be used to test which of the following hyp. scenarios? *BOTH-SIDED* The average waiting time per customer at a fast food restaurant has been 7.5 minutes. The customer waiting time has a normal distribution. The manager claims that the use of a new cashier system will decrease the average customer waiting time in the store. A random sample of 12 customer transactions has been recorded, At a significance level o f.05, what is the rejection point condition? We would reject the null hyp if: *t < -1.796* As the level of significance increases, we are more likely to reject the null hypothesis. *TRUE* When carrying out a large sample test of Ho: mu = 10 vs. Ha: mu > 10 by using a rejection point, we reject Ho at level of significance when the calculated test statistic is: *Greater than Za* The production manager for the XYZ manufacturing company is concerned that the customer orders are being shipped late. He asked one of his planners to check the timeliness of shipments for 1,000 orders. The planner randomly selected 1,000 orders and found that 120 orders were shipped late. What is the 95% confidence interval for the proportion of orders shipped late? *.10 to .14* The following list represents a sample of the ages of the soldiers enlisting in the military: 19, 22, 23, 19, 21, 22, 19, 23, 21. Assume that the population standard deviation is known to be 2 years. Construct a 99% confidence interval for the average ago of the soldier enlisting in the military. *19.28 to 22.72* Alpha is the probability that the test statistic would assume a value as or more extreme than the observed value of the test. *FALSE* Everything else being constant, increasing the sample size decreases the probability of committing a Type II Error. *TRUE* When conducting a hyp. test about a single mean, at a given level of significance, as the sample size n increases, the power of the test: *WILL INCREASE*

When constructing a confidence interval for a sample proportion, the t distribution is appropriate if the sample size is small. *FLASE* When the level of confidence and the sample size remain the same, a confidence interval for a population mean mu will be wider, when the sample standard deviation s is small tan when its large. *FALSE* In class we discussed the use of Confidence Intervals to test which of the following hyp. scenarios? *BOTH-SIDED*

For a given hypothesis test, if we do not reject H0, and H0 is true. -No Error has been Committed In a manufacturing process a random sample of 9 bolts manufactured has a mean length of 3 inches with a standard deviation of .3 inches. What is the 95% confidence interval for the true mean length of the bolt? -2.770 to 3.231 Confidence intervals can be used to test which of the following Hypotheses scenarios? -Both Sided As the level of significance x increases, we are more likely to reject the null hypothesis. -True A statistical quality control process for cereal production measures the weight of a cereal box. The population standard deviation is known to be .06 ounces. In order to achieve a 97% confidence with a margin of error of .02 ounces, how large a sample should be used? .43 When the population is normally distributed, population standard deviation o is unknown, and the sample size is n=15; the confidence interval for the population mean u is based on: -The t distribution

The production manager for XYZ manufacturing company is concerned that the customer orders are being shipped late. He asked one of his planners to check the timeliness of shipments for 1000 orders. The planner Randomly selected 1000 orders and found that 120 orders were shipped late. What is the 95% confidence interval for the proportion of orders shipped late? .10 to .14 The null hypothesis is a statement that will be accepted only if there is convincing sample evidence that is true. -False A confidence interval increases in width as: -All of the above If a null hypothesis is rejected at a significance level of 0.01, it will ______ be rejected at a significance level of 0.05. -Always What value(s) of alpha would we reject HO for U greater than the mean 10 if = 11, S = 2, and N = 36? .05 and .01 When the null hypothesis is true, there is no possibility of making a Type I error. -False A test statistic is computed from sample data in hypothesis testing and is used in making a decision about whether or not to reject the null hypothesis. -True In a manufacturing process, we are interested in measuring the Average length of a certain type of bolt. Past data indicates that the Standard deviation is .25 inches. How many bolts should be sampled in order to

make us 95% confident that the sample mean bolt length is within .02 inches of the true mean bolt length? 601 When carrying out a large sample test of HO: u=10 vs. Ha: u > 10 by using rejection point, we reject that HO at level of significance x when calculated test statistic is: Greater then Za You cannot make a Type II error when the null hypothesis is true. -True The width of a confidence interval will be: -Narrower for 90% confidence than 95% >confidence What sample size would be required to estimate u to within +- 3 with 95% confidence if the population standard deviation is 24.5? 247 In a manufacturing process a random sample of 9 bolts manufactured has a mean length of 3 inches with a variance of .09. What is the 90% confidence interval for the true mean length of the bolt? 2.8140 to 3.8160 The null hypothesis always includes an equal (=) sign. -True(copied from the handwritten notesmay be a little off) -At a given level of significance, as the sample size n increases the power of the test WILL INCREASE -When concluding (or conducting) a hypothesis test about a single mean, other relevant factor(s) held constant(,) increasing the level of significance from .05 to .10 will reduce the probability of a type I error. FALSE

-When the sample size and sample standard deviation remain the same, a 99% confidence interval for a population mean, Q will be ________________ the 95% confidence interval for WIDER THAN -When the level of confidence and the sample size remain the same, a confidence interval for a population mean Q will be _________________, when the sample standard deviation s is small than when s is large. NARROWER -When the sample size and the sample proportion remain the same, a 90% confidence interval for a population proportion p will be __________ the 99% confident interval for p. NARROWER THAN

WIDER THAN

WIDER

TRUE

Makes as large as reasonable possible and makes as close to .25 as reasonably as possible

THE Z DISTRIBUTION Assuming the same value of (, as the sample size increases, the value of tE/2 approaches the value of ZE/2. TRUE There is little difference between the values of tE/2 and ZE/2 when the sample SIZE IS LARGE

When determining the sample size n, if the value found is not an integer initially, we ____________ round this value up to the next integer value. ALWAYS The manager of the quality department for a tire manufacturing company wants to study the average tensile strength of rubber used in making a certain brand of radial tire. The population is normally distributed and the population standard deviation is known. She uses a Z test to test the null hypothesis that the mean tensile strength is less than or equal to 800 pounds per square inch. The calculated Z test Statistic is a positive value that leads to a p-value of .067 for the test. If the significance level is .10, the null hypothesis would be rejected. TRUE A type I error is rejecting a true null hypothesis. TRUE The larger the p-value, the more we doubt the null hypothesis. FALSE When carrying out a large sample test about a population proportion p where we are testing H0: p = .4 vs. HE: p < .4 and z is the calculated test statistic, we reject H0 at level of significance E if and only if Z < - ZE/2 p-value < E When carrying out a large sample test of H0: Q = 10 vs. HE: Q 10 by using a p-value, we reject H0 at level of significance E if and only if the p-value is Less than E/2 If a null hypothesis is not rejected at a significance level of .05, it will _________ be rejected at a significance level of .01. NEVER f we reject H0:Q = 10 in favor of HE:Q 10 at a given level of significance with a positive value of the test statistic z, then if we test H0:Q = 10 versus HE:Q 10 using the same sample, HE:Q > 10 will __________ be rejected at the same significance level. ALWAYS A professional basketball player is averaging 21 points per game. He will be retiring at the end of this season. The team has multiple options to replace him. However, the owner feels that signing a replacement is only justified, if he can average more than 22 points per game. Which of the following are the appropriate hypotheses for this problem? H0: Q 22 vs. HE: Q > 22

View Results

Exam 1

Question 1

(4 points) is also

If the sampled population is exactly normal distribution, then the sampling distribution of expected to be normal regardless of the sample size.


Student Response

Answer Choices a. b. True False

Score:

0/4

Question 2

(4 points)

The z value tells us the number standard deviations that a value x is from the mean. Student response: Correct Response Student Response Answer Choices a. b. True False

Score:

4/4

Question 3

(4 points)

The price-to-earning ratio for firms in a given industry is distributed according to normal distribution. In this industry, a firm with a standard normal variable value of Z = 1: Student response: Correct Student Answer Choices Response Response a. Has an above average price-toearning ratio. b. Has a below average price-toearnings ratio. c. Has an average price-to-earnings ratio. d. May have an above average or below average price-to-earnings ratio.

Score:

4/4

Question 4

(4 points) must be a normal distribution with a mean 0 and standard deviation Student Response Answer Choices a. b. True False

The sampling distribution of 1. Student response: Correct Response

Score:

4/4

Question 5

(4 points)

If the random variable X has a mean of Q and a standard deviation W, then (X - Q)/W has a mean and standard deviation respectively: Student response: Correct Response Student Response Answer Choices a. b. c. d. Q and W and s 1 and 0 0 and 1

Score:

4/4

Question 6

(4 points)

Consider a sampling distribution formed based on n = 3. The standard deviation of the population of all sample means x is ______________less than the standard deviation of the population of individual measurements . Student response: Correct Response Student Response Answer Choices a. b. c. Always Sometimes Never

Score:

4/4

Question 7

(4 points)

The mean life of pair of shoes is 40 months with a standard deviation of 8 months. If the life of the shoes is normally distributed, how many pairs of shoes out of one million will need replacement before 36 months? Student response: Correct Response Student Response Answer Choices a. b. c. d. 500,000 808,500 191,500 308,500

Score:

4/4

Question 8

(4 points)2

Assume that we have selected a random sample of 25 units from a normally distributed large population. If = 15, and = 4, what is the standard deviation of the sampling distribution of Student Response Answer Choices a. b. c. d. e. 15 4 2 1 .4 ? Student response: Correct Response

Score:

0/4

Question 9

(4 points)

A student's grade on an examination was transformed to a z value which is negative. Therefore, we know that he scored: Student response: Correct Response Student Response Answer Choices a. Higher than 16% of the class b. Higher than 45% of the class c. Above the first quartile d. Below the mean e. Lower than 16% of the class

Score:

0/4

Question 10

(4 points)

Which of the following statements is not a property of the normal probability distribution? Student response: Correct Student Answer Choices Response Response a. The normal distribution is symmetric. b. 95.44% of all possible observed values of the random variable x are within plus or minus three standard deviations of the population mean. c. The mean, median, and mode are equal. d. The area under the normal curve to the right of the mean is equal to the area under the normal curve to the left of the mean.

Score:

4/4

Question 11

(4 points)

Which of the following is a valid probability value for a discrete random variable? Student response: Correct Response Student Response Answer Choices a. b. c. d. .2 1.01 -.7 All of the above

Score:

4/4

Question 12

(4 points)

The relationship between the standard normal random variable Z and normal random variable X is that: Student response: Correct Student Answer Choices Response Response a. Only the norma