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13.5 Analyze Surveys and Samples

13.5 Analyze Surveys and Samples. Essential Question: How do you identify populations and sampling methods?. 1. You toss a coin and spin the spinner. How many outcomes are in the sample space?. 2. You spin the spinner twice. How many outcomes are in the sample space?. 25. 10. ANSWER.

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13.5 Analyze Surveys and Samples

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  1. 13.5 Analyze Surveys and Samples Essential Question: How do you identify populations and sampling methods?

  2. 1. You toss a coin and spin the spinner. How many outcomes are in the sample space? 2. You spin the spinner twice. How many outcomes are in the sample space? 25 10 ANSWER ANSWER Lesson 13.5, For use with pages 871-874 Warm-up Exercises A spinner has 5 sections of equal area, with sections numbered 1-5.

  3. Independent Practice CheckTextbook p. 858-859

  4. Independent Practice CheckTextbook p. 864-867

  5. Survey = a study of one or more characteristics of a group • Population = the entire group you want information about • Sample = part of a population actually surveyed Vocabulary

  6. Random Sample = every member of the population has an equal chance of being selected • Stratified Random Sample = the population is divided into distinct groups • Members are selected at random from each group • Systematic Sample = a rule is used to select members of the population • Convenience Sample = only members of the population that are easily accessible are surveyed • Self-Selected Sample = members of the population select themselves by volunteering Sampling Methods

  7. Biased Sample = a sample that is not representative of the population • Biased Question = a question that encourages a particular response Bias

  8. EXAMPLE 1 Classify a sampling method EMPLOYEE SAFETY The owners of a company with several factories conduct a survey to determine whether employees are informed about safety regulations. At each factory, 50 employees are chosen at random to complete the survey. Identify the population and classify the sampling method. SOLUTION The population is all company employees. Because the population is divided into distinct groups (individual factories), with employees chosen at random from each group, the sample is a stratified random sample.

  9. for Example 1 GUIDED PRACTICE 1. What If? In Example 1, suppose the owners survey each employee whose last name begins with M. Classify the sampling method. SOLUTION The population is all company employees. Because the population is divided into distinct groups (individual factories), with employees chosen at systematic sampling method.

  10. EXAMPLE 2 Identify a potentially biased sample In Example 1, suppose the owners question 50 workers chosen at random from one factory. Is the method likely to result in a biased sample? SOLUTION Workers at other factories may hold significantly different opinions, so the method may result in a biased sample.

  11. Tell whether the question is potentially biased. Explain your answer. If the question is potentially biased, rewrite it so that it is not. EXAMPLE 3 Identify potentially biased questions a. Don’t you agree that the voting age should be lowered to 16 because many 16-year-olds are responsible and informed? b. Do you think the city should risk an increase in pollution by allowing expansion of the Northern Industrial Park?

  12. EXAMPLE 3 Identify potentially biased questions SOLUTION a. This question is biased because it suggests that lowering the voting age is a good thing to do. An unbiased question is “Do you think the voting age should be lowered to 16?” b. This question is biased because it suggests that the proposed expansion will be bad for the environment. An unbiased question is “Do you think the city should allow expansion of the Northern Industrial Park?”

  13. ANSWER The sample method will likely result in a biased sample because it is such a small sample and from one location. for Examples 2 and 3 GUIDED PRACTICE Soccer 2. In a survey about Americans’ interest in soccer, the first 25 people admitted to a high school soccer game were asked, “How interested are you in the world’s most popular sport, soccer?” a. Is the sampling method likely to result in a biased sample? Explain.

  14. ANSWER This question is biased because it promotes an opinion within the question. “How interested are you in soccer?” would be an unbiased way of asking the question. for Examples 2 and 3 GUIDED PRACTICE b. Is the question potentially biased? Explain your answer. If the question is potentially biased, rewrite it so that it is not.

  15. How do you identify populations and sampling methods? Essential Question:

  16. Textbook p. 873-874 Independent Practice

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