Analyze Surveys and Samples

6.6 pg. 359

Vocabulary

Survey- a study of one or more characteristics of a

group.

Population- the entire group you want information

about.

Sample- part of the population.

Biased Question- a question that encourages a

particular response.

7 Samples

1. Random Sample- every member has an equal chance of being selected.

2. Stratified Random Sample- population is divided into distinct groups. Members are selected at random from each group.

3. Systematic Sample- a rule is used to select members.4. Convenience Sample- only members who are easily

accessible are selected.5. Self-selected Sample- members select themselves by

volunteering.6. Representative Sample- a sample that accurately

reflects the characteristics of a population.7. Biased Sample- a sample that is not representative of

the population.

Example1. A university is conducting a survey to

determine whether a public library has hours of business that satisfy most of its patrons. At the library, students question every tenth library patron who exits the library. Identify the population and classify the sampling method.

2. Suppose the university students conduct the survey by asking all patrons checking out books to fill out a form and mail it back to the university. Classify the sampling method.

Example3. Suppose the university students question 20

library patrons chosen at random on a Monday morning between 9:00am and 11:00am. Is this method likely to result in a representative sample or a biased sample? Explain.

Example

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

a. Because there is a lack of affordable entertainment for teenagers in the city, do you think the city should sponsor more youth activities?

b. Do you think the city should risk an increase in taxes by allowing a new elementary school to be built?

Example5. In a survey about the need to improve driver safety,

50randomly selected adults at a senior-citizen resident

facilitywere asked, “Do you think driver safety would improve if rivers were required to pass a driving test every ten yearsthen renewing a driver’s license?”a. Is the sampling method likely to result in a

representative sample or a biased sample? Why?

b. Is the question potentially biased? Explain?

Homework

TextbookPg. 361 1-11