AP Stats Chapter 4

The web portal AOL places opinion poll questions next to many of its news stories. Simply click your response to join the sample. One of the questions in January 2008 was "Do you plan to diet this year?" More than 30,000 people responded, with 68% saying "Yes." You conclude that

• about 68% of Americans planned to diet in 2008

• the poll used a convenience sample, so the results tell us little about the population of all adults.

• the poll uses voluntary response, so the results tell us little about the population of all adults.

• the sample is too small to draw any conclusions.

Your statistics class has 30 students. You want to call an SRS of 5 students from your class to ask where they use a computer for the online quizzes. You label the student 01, 02, ..., 30. You enter the table of random digits at this line: 14459 26056 31424 80371 65103 62253 22490 61181 Your SRS contains the students listed:

• 14,45,92,60,56

• 14,31,03,10,22

• 14,03,10,22,22

• 14,03,10,22,06

• 14,03,10,22,11

Suppose that 35% of the registered voters in a state are registered as Republicans, 40% as Democrats, and 25% as Independents. A newspaper wants to select a sample of 1000 registered voters to predict the outcome of the next election. If they randomly select 350 Republicans, randomly select 400 Democrats, and randomly select 250 Independents, did this sampling procedure result in a simple random sample of registered voters from this district?

• Yes, because each registered voter had the same chance of being chosen.

• Yes, because random chance was involved.

• No, because not all registered voters had the same chance of being selected.

• No, because there were a different number of registereed voters selcted from each party.

• No, because not all possible groups of 1000 registered voters had the same chance of being chosen.

An SRS of 1200 adult Americans is selected and each person is asked the following question: "In light of the huge national deficit should the government at this time spend additional money to establish a national system of health insurance?" Only 39% of those responding answered "Yes." This survey

• is reasonably accurate since it used a large SRS.

• needs to be larger since only about 24 people were drawn from each state.

• probably understates the percent of people who favor a system of national health insurance.

• is very inaccurate but neither understates nor overstates the percent of people who favor a system of national health insurance. Because an SRS was used, the survey is unbiased.

• probably overstates the percent of people who favor a system of national health insurance.

Is this a probability distribution?

• No

• Yes

Is this a probability distribution?

• No, the sum of p(x) does not equal 1.

• Yes, all p(x) are between 0 and 1.

• No, all p(x) are not between 0 and 1.

• Yes, the sum p(x) is 1.

• A

• B

• C

• D

• E

A sample of student opinion at a Big Ten University selects an SRS of 200 of the 30,000 undergraduate students and a another SRS of 100 of the 5,000 graduates. What is the term for this kind of sample?

• Simple random sample

• Simple random sample with blocking

• Stratified random sample

• Cluster random sample

• Systematic random sample

An Illinois school district wants to compare the effectiveness of a standard AP Statistics curriculum and a new “hands-on” AP Statistics curriculum. Two experienced teachers, Mrs. Militello and Mrs. Grozik, each teach one class with the standard curriculum and one with the new approach. Students are assigned at random to these four classes. At the end of the year, all students take the AP Statistics exam. Which of the following are the experimental units in this experiment?

• Mrs Militello and Mrs Grozik

• The two AP Statistics curriculum

• The students in the four classes

• The students taking the AP exam in IL

• The four classes

A program that was intended to cure a person’s fear of spiders was offered at a local zoo. Volunteers with a fear of spiders participated in the program, which included holding a spider for 15 minutes. One month after they completed the program, the participants were contacted and surveyed about the program. Over 90 percent of the participants claimed they were cured of their fear of spiders. Based on the description of the program, which of the following statements is true?

• Because over 90% of the participants claimed to be cured, the results prove that holding a spider will cure a person’s fear of spiders.

• Because over 90% of the participants claimed to be cured, the results can be generalized to the population of all people who have a fear of spiders.

• Because the participants were volunteers, the study is a census of all people in the local area who have a fear of spiders.

• Because the participants were self-selected, a person’s desire to be cured could be a confounding variable.

• Because participants held a spider for 15 minutes, the study is an experiment and the results can be generalized to the population of all people who have a fear of spiders.