STATISTICS 8 CHAPTERS 1 TO 6, SAMPLE （统计8章1到6,样本）.pdf

STATISTICS 8 CHAPTERS 1 TO 6, SAMPLE MULTIPLE CHOICE QUESTIONS Correct answers are in bold italics.. This scenario applies to Questions 1 and 2: A study was done to compare the lung capacity of coal miners to the lung capacity of farm workers. The researcher studied 200 workers of each type. Other factors that might affect lung capacity are smoking habits and exercise habits. The smoking habits of the two worker types are similar, but the coal miners generally exercise less than the farm workers. 1. Which of the following is the explanatory variable in this study? a. Exercise b. Lung capacity c. Smoking or not d. Occupation 2. Which of the following is a confounding variable in this study? a. Exercise b. Lung capacity c. Smoking or not d. Occupation This scenario applies to Questions 3 to 5: 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. 3. This is a randomized experiment rather than an observational study because: a. Blood pressure was measured at the beginning and end of the study. b. The two groups were compared at the end of the study. c. The participants were randomly assigned to either walk or read, rather than choosing their own activity. d. A random sample of participants was used. 4. The two treatments in this study were: a. Walking for half an hour three times a week and reading a book for half an hour three times a week. b. Having blood pressure measured at the beginning of the study and having blood pressure measured at the end of the study. c. Walking or reading a book for half an h