It sounds more impressive when reported as in the

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people. (It sounds more impressive when reported, as in the article, as a 47 percent reduction in the risk of heart attack. Results can be misleading when the occurrence of E in one group is reported as a percentage of its occurrence in the other. If there had been two heart attacks in the control group and only one in the experimental group, we’d have a case of a “whopping” 50 percent reduction in heart attack risk, but with practically no statistical significance, since one more heart attack in one of the groups is certainly attributable to chance.) Still, this study does support the conclusion that taking the aspirin cuts the risk of heart attack. But before we all go reaching for the aspirin bottle, we want to remind you that aspirin can riddle your duodenum if you tend toward ulcers. You pays your money and you takes your choice. 9. The South African, French, and Canadian studies are nonexperimental effect-to-cause studies. The Southern Illinois–Florida State study is experimental cause-to-effect. The hypotheses tested were that cigarette smoking causes (vascular-associated) impotence and that nicotine causes an immediate reduction in sexual arousal. The South African study mentions no control group. We can only presume that something less than 93 percent of the South IM – 11 | 9
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African male population are smokers (but see below). In the U.S. study, we assume that the forty-two-member sample was divided into three groups of equal size to be administered high- nicotine cigarettes, low-nicotine cigarettes, and mints. The frequency of cause in the South African study is 93 percent, which, as noted, is probably higher than the incidence of smokers in the target population. No difference is specified in the U.S. study, although the report leads one to believe that slow arousal was universal among the high-nicotine cigarette smoker. There is no specific indication of significance in the report, except on the “universal” reading given to the U.S. study. Based on this passage, we’re not sure how much confidence we’d have in the results, especially because of the nonexperimental nature of the South African, French, and Canadian studies. It may be, for instance, that the percentage of alcohol drinkers among smokers is higher than normal, and that alcohol plays a significant role in some kinds of impotence. 10. The causal hypothesis is that high doses of androgens reduce HDL levels in the blood of adult human males. The study is nonexperimental cause-to-effect. The experimental group consisted of sixteen healthy, “well-conditioned” men in their early thirties who took androgens for four weeks as part of their weight-training program. The control group consisted of the same men before using androgens, all of whom had normal levels of HDLs. The HDL levels in the experimental group decreased by 60 percent.
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It sounds more impressive when reported as in the article...

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