AP Stats Unit 9 Practice

Hint 1: Use inverse Normal model

Hint 2: Find SD...use algebra

Hint 3: Use normal model

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• E

Hint 1: Is this binomial or geometric?

Hint 2: Use formula sheet/calculator.

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• E

If a researcher were to interview every 10th student who enters the school in the morning. What type of sampling is this?

• simple random

• voluntary response

• systematic

• convenience

Disneyland often surveys its guests as they exit a restaurant during their visit. The surveyor stands at the restaurant exit, counts the number of people leaving, and surveys every 25th guest.
This is a form of:

• Simple Random Sample

• Stratified Random Sample

• Voluntary Response

• Systematic Random Sampling

Chloe and Danna want to determine the favorite subject of all students in the middle school. So they place every middle school student's name in a bucket and choose 30 to poll.

• Biased sample

• Random sample

You want to take a simple random sample (SRS) of 50 of the 816 students who live in a dormitory on campus. You label the students 001 to 816 in alphabetical order. In the table of random digits, you read the entries (shown in the image).

The first three students in your sample have labels

• 955, 929, 400

• 400, 769, 769

• 559, 294, 007

• 929, 400, 769

• 400, 769, 335

The transportation department of a large city wants to estimate the proportion of residents who would use a system of aerial gondolas to commute to work. The gondolas would be part of the city’s effort to relieve traffic congestion. The department asked a random sample of residents whether they would use the gondolas. The residents could respond with yes, no, or maybe. Which of the following is the best description of the method for data collection used by the department?

• A census

• A sample survey

• An experiment with a completely randomized design

• An experiment with a randomized block design

• An experiment with a matched-pairs design

A compact disc (CD) manufacturer wanted to determine which of two different cover designs for a newly released CD will generate more sales. The manufacturer chose 70 stores to sell the CD. Thirty-five of these stores were randomly assigned to sell CDs with one of the cover designs and the other 35 were assigned to sell the CDs with the other cover design. The manufacturer recorded the number of CDs sold at each of the stores and found a significant difference between the mean number of CDs sold for the two cover designs. Which of the following gives the conclusion that should be made based on the results and provides the best explanation for the conclusion?

• It is NOT reasonable to conclude that the difference in sales was caused by the different cover designs because this was not an experiment.

• It is NOT reasonable to conclude that the difference in sales was caused by the different cover designs because there was no control group for comparison.

• It is NOT reasonable to conclude that the difference in sales was caused by the different cover designs because the 70 stores were not randomly chosen.

• It is reasonable to conclude that the difference in sales was caused by the different cover designs because the cover designs were randomly assigned to stores.

• It is reasonable to conclude that the difference in sales was caused by the different cover designs because the sample size was large.

To find out the average occupancy size of student-rented apartments, a researcher picks a simple random sample of 100 such apartments. Even after one follow-up visit, the interviewer is unable to make contact with anyone in 27 of these apartments. Concerned about nonresponse bias, the researcher chooses another simple random sample and instructs the interviewer to continue this procedure until contact is made with someone in a total of 100 apartments. The average occupancy size in the final 100-apartment sample is 2.78. Is this estimate probably too low or too high?

• Too high, because of undercoverage bias.

• Too high, because convenience samples overestimate average results.

• Too high, because voluntary response samples overestimate average results.

• Too low, because of undercoverage bias.

• Too low, because convenience samples overestimate average results.

A program exists to encourage more middle school students to major in math and science when they go to college. The organizers of the program want to estimate the proportion of students who, after completing the program, go on to major in math or science in college. The organizers will select a sample of students from a list of all students who completed the program. Which of the following sampling methods describes a stratified random sample?

• Select all female students on the list.

• Randomly select 50 students on the list.

• Randomize the names on the list and then select every tenth student on the randomized list.

• Randomly select 25 names from the female students on the list and randomly select 25 names from the male students on the list.

• Randomlyselect50studentsonthelistwhoareattendingcollege.