Worksheet 13.3 and 13.4Name: Date:

Name the sampling method that best describes each situation.

Each question refers to the Discrete University of Mathematics (DUM) student body. There are 400 freshmen, 300 sophomore, 300 junior, and 200 senior DUM students.

1.)Nosey Nelly wants to know how the rest of the class did on the last test. She peeks at the scores of a few students sitting near her. Based on what she sees, she concludes that nobody did very well.

2.)On a day when every student is present, the students are given a Safety Questionnaire. Each student fills out the Questionnaire.

3.)The student newspaper conducts a poll of student opinion regarding the rumor that the football coach is about to be fired. In the poll, 20 freshmen, 15 sophomores, 15 juniors, and 10 seniors are randomly selected to be interviewed.

4.)The Student Government Association also wants to get student opinion. They station pollsters at the entrance of the football game on Friday with each instructed to conduct 40 polls.

5.)The coach chooses the three captains for Friday’s game by putting the names of all the players in a helmet and drawing out three names.

6.) The coach needs to choose a senior MVP. He instructs the cheerleaders to place jugs at the concession stand with a senior player’s photo on each for donations. Whichever player receives the highest donations will be the MVP.

Answer the questions based on the following true story.

In 1988, “Dear Abby” asked her readers to let her know whether they had cheated on their spouses or not. The readers’ responses are summarized in the following table.

STATUS / WOMEN / MEN
Faithful / 127,318 / 44,807
Unfaithful / 22,468 / 15,743
Total / 149,786 / 60,550

Based on the results of this survey, “Dear Abby” concluded that the amount of cheating among married couples is much less than people believed. (In her words, “The results were astonishing. There are far more faithfully wed couples than I had surmised.”)

1.)Why was this a survey, rather than a census?

2.)Describe the target population.

3.)Describe the sampling frame.

4.)How was the sample chosen?

5.)What percentage of the women in the survey claimed to be faithful?

6.)Would this percentage be a statistic or parameter or neither? Explain.

7.)What, if any, bias would this survey be subjected to?

8.)Based on the data, estimate the percentage of married men that are faithful.

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