Test Bank For Mind On Statistics 5th Edition By Utts

Test Bank For Mind On Statistics 5th Edition By Utts

Chapter 1

Sections 1.1 – 1.3

Questions 1 to 3: Suppose you were to read about a study showing that people who sleep less than five hours a night have twice as much risk of premature death as people who sleep seven or eight hours a night.

1. Can you conclude that sleeping shorter hours causes a higher risk of premature death?
   1. No, because the result was clearly based on an observational study.
   2. Yes, because the result was clearly based on a randomized experiment.
   3. The answer depends on whether the research was based on an observational study or a randomized experiment, and it isn’t obvious which was used.
   4. No, because the baseline risk of premature death is not given.

KEY: A

2. The “baseline risk” in this context is
   1. the risk of premature death for people who sleep less than five hours a night.
   2. the risk of premature death for people who sleep seven or eight hours a night.
   3. the risk of premature death for all people.
   4. the risk of premature death at the beginning of the study for those in the study.

KEY: B

3. Which of the following is not an example of a possible “confounding variable” in this study?
   1. Medications a person is taking.
   2. The amount of alcohol a person drinks in the evening.
   3. The amount of stress a person is under in their work.
   4. The amount of sleep a person gets per night.

KEY: D

Questions 4 to 6: A randomized experiment was done by randomly assigning each participant either to walk for half an hour three times a week or to sit quietly reading a book for half an hour three times a week. At the end of a year the change in participants’ blood pressure over the year was measured, and the change was compared for the two groups.

4. This is a randomized experiment rather than an observational study because
   1. blood pressure was measured at the beginning and end of the study.
   2. the two groups were compared at the end of the study.
   3. the participants were randomly assigned to either walk or read, rather than choosing their own activity.
   4. a random sample of participants was used.

KEY: C

5. The two treatments in this study were
   1. walking for half an hour three times a week and reading a book for half an hour three times a week.
   2. having blood pressure measured at the beginning of the study and having blood pressure measured at the end of the study.
   3. walking or reading a book for half an hour three times a week and having blood pressure measured.
   4. walking or reading a book for half an hour three times a week and doing nothing.

KEY: A