AP Stats Ch. 4 Review

_______ is a part of a group being surveyed.

• Sample
• Population
• Random Sample
• Quartile

_______ is the entire group of objects or individuals considered for a survey.

• Sample
• Population
• Random Sample
• Quartile

A school psychologist wants to investigate student depression. She selects, at random, samples of 30 freshmen, 30 sophomores, 30 juniors, and 30 seniors to interview. Which of the following best describes the principal's sampling plan?

• A convenience sample

• A simple random sample

• A stratified random sample

• A cluster sample

• A systematic sample

Which of the following is a true statement?

• If bias is present in a sampling procedure, it can be overcome by dramatically increasing the sample size

• There is no such thing as a “bad sample”

• Sampling techniques that use probability techniques effectively eliminate bias

• Convenience samples often lead to undercoverage bias

• Voluntary response samples often underrepresent people with strong opinions

Which of the following is a true statement about sampling error (variation)?

• Sampling error can be eliminated only if a survey is both extremely well designed and extremely well conducted.

• Sampling error concerns natural variation between samples, is always present, and can be described using probability.

• Sampling error is generally larger when the sample size is larger.

• Sampling error implies an error, possibly very small, but still an error, on the part of the surveyor.

• Sampling error is higher when bias is present.

Many colleges are moving toward coed dormitories. A Residential Life director plans to sample student attitudes toward this arrangement. He randomly selects three of the 12 dorms and sends a questionnaire to all residents living in them. Which of the following best describes the director’s sampling plan?

• A convenience sample

• A simple random sample

• A stratified sample

• A cluster sample

• A systematic sample

Two studies are run to compare the experiences of families living in high-rise public housing to those of families living in townhouse subsidized rentals. The first study interviews 25 families who have been in each program for at least one year, while the second randomly assigns 25 families to each program and interviews them after 1 year. Which of the following is a true statement?

• Both are observational studies because of the time period involved

• Both studies are observational studies because there are no control groups

• The first study is an observational study, while the second is an experiment

• The first study is an experiment, while the second is an observational study

• Both studies are experiments

A consumer product agency tests miles per gallon for a sample of automobiles using each of four different octanes of gasoline. Which of the following is true?

• There are four explanatory variables and one response variable

• There is one explanatory variable with four levels of response

• Miles per gallon is the only explanatory variable, but there are four response variables corresponding to the different octanes

• There are four levels of a single explanatory variable

• Each explanatory level has an associated level of response

You want to take a simple random sample (SRS) of 25 of the 729 people who live in a apartment complex in a city. You label the people 001 to 729 in alphabetical order. In the table of random digits, you read the entries

65792 84097 61760 32544 75450 36662 87194 04873

The first three people in your sample have labels

• 409, 325, 447, 036

• 657, 928, 409, 761

• 657, 409, 325, 447

• 761, 760, 036, 662, 871

• 409, 325, 036, 662

A gardener wants to try difference combinations of fertilizer (none, 1 cup, 2 cups) and mulch (none, wood chips, pine needles, plastic) to determine which combination produces the highest yield for a variety of green beans.  He has 60 green-bean plants to use in the experiment.  If he wants an equal number of plants to be assigned to each treatment, how many plants will be assigned to each treatment?

• 3
• 4
• 5
• 12