23. You need to select three subjects from a list of nine subjects. The subjects’ names are provided below. 1. Berliner 4. Wolfe 7. Verducci 2. Blumenthal 5. Stasny 8. Lin 3. MacEachern 6. Santner 9. Critchlow Use the numerical labels attached to the names and the following list of random digits to select three individuals. Read the list of random digits from left to right, starting at the beginning of the list. 44982 20751 27498 12009 45287 71753 98236 66419 84533 11793 20495 05907 11384 Which of the following statements is TRUE? If we used another list of random digits to select the sample, we would get a completely different sample than that obtained with the list actually used. If we used another list of random digits to select the sample, the result obtained with the list actually used would be just as likely to be selected as any other set of three names. If we used another list of random digits to select the sample, we would get the same result as obtained with the list actually used. If we used another list of random digits to select the sample, we would get at most one name in common with a name obtained with the list actually used.
24. An experiment has a double-blind design when neither the investigators nor the subjects know or meet each other before the study is over. know that an experiment is going on. know which subjects have been assigned to which treatments in a list of known treatment options. know the purpose of experiment.
25. The drug valproate has been shown in mice to facilitate adult learning of skills typically acquired during early life. A study enrolled healthy adult males with no advanced musical training and taught them to identify absolute pitch, a rare ability typically learned in early childhood. In a first stage, the participants were randomly assigned to valproate or a placebo. In a second stage, the conditions were reversed, so that a participant who received the placebo first took valproate for the second stage, and vice versa. This is an example of a(n) experiment with a block design. case-control observational study. matched pairs or repeated measures experiment. completely randomized experiment. 26. The Physicians’ Health Study followed 22,000 male physicians for a period of several years. About 11,000 took an aspirin every second day, while the rest took a placebo. At the completion of the study, it was noted whether a subject had experienced a heart attack during the period of the study. It was found that the aspirin group had significantly fewer heart attacks than the placebo group. The factor in the experiment is the medication used (aspirin or placebo). use of a placebo. severity of the heart attack. length of the study. 27. A study attempts to determine whether a new medication is effective at lowering blood pressure. Forty subjects with hypertension who volunteer to participate in the study are to be given both the new medication and a placebo. The order in which each subject receives the treatment is randomized and the subject does not know which treatment they are getting. Each treatment is administered for four weeks. At the end of each four-week period a subject’s blood pressure is recorded. This is an example of the placebo effect. a double-blind observational study. a stratified analysis. a matched pairs experiment.
28. Consumer Reports compared the effectiveness of an anti-wrinkle cream with that of a plain moisturizer in reducing the appearance of wrinkles. They enrolled 79 subjects with moderate to marked wrinkles, and instructed them to use both products, one on each side of the face, every morning for 12. The subjects didn’t know which products they were using. At the end of the study, panelists examined “before and after” photos of the subjects to assess wrinkle appearance. The panelists did not know which product the subjects had used. Which of the following statements is TRUE? This study was a randomized, double-blind experiment. This study was a double-blind experiment, but not a randomized experiment. This study was an experiment, but not a double-blind experiment. This study is just anecdotal.
29. A researcher is trying to determine the proportion of a certain species of fish in a local lake. After sampling 40 fish, she found 32 of them were the species of interest. She estimates the probability that the next fish is of the species of interest to be 0.50. 1.25. 0.32. 0.80. 30. Event A has probability 0.4. Event B has probability 0.5. If A and B are disjoint, then the probability that both events occur is 0.1. 0.9. 0.2. 0.0.