The population is ___________________________.

6.6 Analyze Surveys and Samples

Example 1 Classify a sampling methodClassify a sampling method

Study Time A high school is conducting a survey to determine the average number of hours that their students spend doing homework each week. At the school, only the members of the sophomore class are chosen to complete the survey. Identify the population and classify the sampling method.

Solution

Because a rule (sophomore class only) is used to select members

of the population, the sample is a ____________ sample.

all of the school’s students

systematic

6.6 Analyze Surveys and Samples

Example 2 Identify a potential biased sampleIdentify a potential biased sample

Is the sampling method used in Example 1 likely to result in a biased sample?

Solution

Students in other grades may have different study habits, so the

method ____________ in a biased sample.may result

6.6 Analyze Surveys and Samples

Example 3 Identify potentially biased questionsIdentify potentially biased questions

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

a. Do you still support the schools basketball team, even though the team is having its worst season in 5 years?

Solutiona. The question is biased because _______________

_________________________________________

________________________.

it suggests that

people should not support a basketball team that is doing poorly

An unbiased question is, “__________________

___________________________”

Do you support

the school basketball team?

6.6 Analyze Surveys and Samples

Example 3 Identify potentially biased questionsIdentify potentially biased questions

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

b. Don’t you think that dogs are better pets than cats?

Solutionb. The question is biased because _______________

____________________________.

it suggests that

dogs are better pets than cats

An unbiased question is, “__________________

________________________”

Do you think dogs

or cats make better pets?

6.6 Analyze Surveys and SamplesCheckpoint. Complete the following exercises. Checkpoint. Complete the following exercises. 1. In Example 1, suppose the school

asks students to volunteer to take the survey. Classify the sampling method.

Self-selected sample

6.6 Analyze Surveys and SamplesCheckpoint. Complete the following exercises. Checkpoint. Complete the following exercises. 2. An amusement park owner wants to evaluate

the customer service given by the park’s ride operators. On day, every 10th customer leaving the park was asked, “Don’t you think our friendly, well-trained ride operators provided excellent customer service today?”

No.a. Is the sampling method likely to result in a biased sample?

Explain.

In this systematic sample, the rule to choose survey

participants is not biased.

6.6 Analyze Surveys and SamplesCheckpoint. Complete the following exercises. Checkpoint. Complete the following exercises. 2. An amusement park owner wants to evaluate

the customer service given by the park’s ride operators. On day, every 10th customer leaving the park was asked, “Don’t you think our friendly, well-trained ride operators provided excellent customer service today?”

This question is biased because it suggests that the ride operators did provide excellent customer service.

b. Is the question potentially biased? Explain your answer. If the question is potentially biased, rewrite it so that it is not.

An unbiased question is “Do you think that our ride operators provided excellent customer service?”

6.6 Analyze Surveys and Samples

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