9-5 making predictions warm up warm up lesson presentation lesson presentation problem of the day...

9-5 Making Predictions

Warm UpWarm Up

Lesson PresentationLesson Presentation

Problem of the DayProblem of the Day

Lesson QuizzesLesson Quizzes


Warm Up

Solve each proportion.1. Which represents a greater amount:

0.04 or 3.9 percent?

2. A bag contains 9 lettered tiles. There are 5 Es, 3 Ts, and 1 X. What letter would you be most likely to draw?An E

0.04


Problem of the Day

After several tries, Carla figures that the

probability of her flipping a playing card into a

hat is . If she was successful on 3 tries, how

many times did she miss?21

1 8


MA.7.P.7.2 Determine, compare, and make predictions based on experimental or theoretical probability…Also MA.7.P.7.1

Sunshine State Standards


Vocabulary

prediction


A prediction is something you can reasonably expect to happen in the future. Weather forecasters use several different methods of forecasting to make predictions about the weather.

One way to make a prediction is to use probability.


Lawrence finds that his experimental probability of getting a hit is 40%. Out of 350 at-bats, how many times can he expect to get a hit?

Additional Example 1: Using Experimental Probability to Make Predictions

Multiply the probability by the number of at bats.

· 350 = x4

10

Method 1: Set up an equation.

140 = x


Think: 4 out of 10 is how many out of 350.

Method 2: Set up a proportion.

The cross products are equal.

Multiply.

4 · 350 = 10 · x

Lawrence can predict that he will get a hit about 140 of 350 times.

Additional Example 1 Continued

1400 = 10xDivide each side by 10 to isolate the variable.

140 = x

10 10

4 10

= x 350


74100

Check It Out: Example 1

Marty finds the experimental probability of him making a field goal to be 74%. Out of 150 field goal attempts, how many times can he expect to make a field goal?

150 = 111


A spinner has eight sections of equal size. Three sections are labeled 1, two are labeled 2, and the others are labeled 3, 4, and 5. In 50 spins, how often can you expect to spin a 1?

Additional Example 2: Using Theoretical Probability to Make Predictions

3 · 50 = 8 · x

P(spinning a 1) = 3 8


18.75 = x

3 8

= x 50


Multiply150 = 8x

You can expect to spin a 1 about 19 times.

8 8 Divide each side by 8 to isolate the variable.


Round to a whole number if it makes sense in the given situation.

Helpful Hint



Rhonda rolls a number cube 330 times. How many times can she expect to roll a 5?

16

= x330 ; x = 55


The Singh family is planning a 7-day tropical vacation during July or August. The island destination they have chosen averages 21 rainy days during this 62-day period. If the Singhs would like to avoid rain on at least 5 days of their vacation, should they go to this spot or choose another?

Additional Example 3: Problem Solving Application


11 Understand the Problem

The answer will be whether the Singh family should go to the island.

List the important information:

• The island destination averages 21 rainy days out of 62 days.

• The Singhs want to avoid rain on at least 5days of their vacation.



22 Make a Plan

On average 21 out of the 62 days it is rainy. Afterfinding out the number of rainy days there shouldbe forecast, subtract to find the number of notrainy days.



Solve33




Multiply.

21 · 7 = 62 · x

7 – 2 = 5

21 62

= x 7

Divide each side by 62 to isolate the variable.

147 = 62x

2.37 ≈ x There will be more than 2 rainy days in 7 days.

Subtract the predicted number of rainy days from the total vacation days.

62 62


Look Back44

They should choose a different location. It islikely to rain more than 2 days (about 2.4 days)during a 7-day period, which will not give theSinghs at least 5 sunny days.


21 rainy days 62 total days

≈ 20 60

or 33%

2.4 rainy days 7 total days

≈ 2 7

or 30%

Since both ratios are about 30%, the answer isreasonable.


The Berry family is planning a 12-day vacation to a beach. The beach they have chosen averages 45 rainy days during this 109-day period. If the Berrys would like to have no rain on at least 7 days of their vacation, should they go to this spot or choose another?



Check It Out: Example 3 Continued

109x = 540

x 12

= 45 109

x ≈ 4.95

There will be about 5 rainy days during a 12-day period, which leaves 7 non-rainy days. The Berry family should go to this beach.


Standard Lesson Quiz

Lesson Quizzes

Lesson Quiz for Student Response Systems


Lesson Quiz: Part I

1. The experimental probability of Maura shooting a goal in field hockey is 12%. Out of 300 shots, how many can Maura predict will be goals?

2. If Scott flips two quarters 25 times, how many times can he expect to flip two heads?

6 times

32


Lesson Quiz: Part II

3. The Aurelio family is planning a 12-day skiing trip during December or january. The region they have chosen gets the right conditions for skiing 46 days during the 62-day period. The Aurelios would like to spend at least 8 days skiing. Will their destination be a good choice?Yes. There will be at least 8 days with the right conditions for skiing.


1. Katia finds the probabilty that the traffic light is red when she reaches an intersection is 45%. In one month, she goes through the intersection 65 times. How many times can she expect the light to be red when she reaches the intersection?

A. 22

B. 26

C. 30

D. 45



2. If you roll a number cube 12 times, about how many times do you expect to roll a number less than five?

A. 6

B. 8

C. 10

D. 12


9-5 making predictions warm up warm up lesson presentation lesson presentation problem of the day...

Documents