11.4 Collecting Data and Circle graphsES: Gather and Organize Information

1.) What percent of the budget is spent on rent?

2.) How much money do the Milton's spend on rent?

3.) What does the least percent of their budget go to?

4.) How much do they spend on this per month?

Circle GraphShows how parts of a group compare to the whole group

($6,000 per month)

The circle graph below shows the results of a survey that asked people at a super market what type of milk they most often drink. Use the graph to answer the following questions.

1.) How many people were surveyed?

2.) How many people drink skim milk?

3.) What percent of the people surveyed drink skim milk>

4.) What percent drink reduced fat?

Conducting a Survey

You can conduct a survey to collect data about a group. You could survey a sample of the population. A. ) population- the entire group

B.) sample - part of the group 

Random sample - every member of the population has an equal chance at being selected

Systematic sample- a rule is used to select members of the population

Stratified sample - the population is divided into distinct groups. Members are selected from each group

Convenience sample - only members of the population who are easily accessible are selected

Self-selected sample - members of a populations volunteer

Sampling methods:

For each survey, describe the population and tell the type of sampling method.

1.) A school newspaper reporter asks every fifth student entering the building whether a new gymnasium should be built.

2.) A manager at a television station randomly telephones 75 residents under 30 years old and 75 residents over 30 years to determine the station's most watched programs.

3.) Describe one way you could randomly select members to participate in a survey.

When conducting a survey, you want a sample to be representative of the population.

biased sample- a sample that is not representative of the population

Since the sampling method can affect how representative a sample is, the most reliable way to select members to survey is random sampling.

biased question- questions that encourage a particular response

When creating a survey question, you should avoid biased questions.

Tell whether the question is biased. Explain your reasoning. If the question is biased rewrite it so it is not.

1.) Don't you agree that planting more trees will make our town more beautiful?

2.) Are you willing to pay higher taxes so the city can build a new stadium, even thought we already have a stadium?

3.) How many times a week do you eat a sandwich?

Demonstrate Understanding:

A school newspaper is conducting a survey to predict the student attendance at the next sports event. Tell whether the sampling method is random, systematic, stratified, convenience, or self-selected.

1. Set up a booth where students can come to give their opinion.

2. Assign a number to every student in the school and have a computer randomly choose the numbers.

Tell whether the question is potentially biased. Explain youranswer. If the question is biased, rewrite it so that it is not.

3.) Don't you think that puppies are the cutest animals?

4.) Which color do you like better, pink or yellow?

5. Do you still support the mayor even though he is raising taxes this year?