TESTING A CLAIM ABOUT A DIFFERENCE BETWEEN TWO PROPORTIONS
DOES TAKING ASPIRIN HELP PREVENT HEART ATTACKS? The subjects in this experiment were 22,071 male physicians. About half (11,037) of these subjects took an aspirin tablet every other day and the remaining subjects (11,034) took a dummy pill that looked and tasted like the aspirin but had no active ingredient. After several years, 239 of the control group but only 139 of the aspirin group had suffered heart attacks.
1. Does this study provide convincing evidence that aspirin helps prevent heart attacks for healthy male physicians like those in this study? Justify your answer.
2. Based on your conclusion in Question 1, is it possible you made a Type I error or a Type II error? Explain.
3. Should you generalize the result in Question 1 to all healthy males? Why or why not?