Question

For questions 16-19, use the following information. The Physicians’ Health Study began in 1982 to test whether low-dose aspirin was beneficial in reducing myocardial infarctions (i.e., heart attacks). The study population consisted of 22,000 male physicians who were randomly assigned to either a low-dose aspirin or a placebo group. These physicians were followed for five years. In the sample, 50% received low-dose aspirin, 1.7% had myocardial infarctions, and 97.8% of the physicians in the placebo group did not have a myocardial infarction. Note that you do not need to use probability for any part of this problem. Round your answers to the nearest whole number. 16. How many physicians had a myocardial infarction? 17. How many physicians were in the placebo group? 18. How many physicians in the placebo group had a myocardial infarction? 19. How many physicians on low-dose aspirin did not have a myocardial infarction?

16. How many physicians had a myocardial infarction?

17. How many physicians were in the placebo group?

18. How many physicians in the placebo group had a myocardial infarction?

19. How many physicians on low-dose aspirin did not have a myocardial infarction?

Answer 1

It is given that the population consisted of 22,000 male physicians who were randomly assigned to either a low-dose aspirin or a placebo group.

It is given that 50% received low-dose aspirin.

Thus, number of physicians assigned to low-dose aspirin group = 50% of 22000

=(50/100)*22000 = 11000 .

Thus, among 22,000 male physicians, 11000 were assigned to low-dose aspirin.

16) It is given that 1.7% of the physicians had myocardial infarction

Thus, number of physicians who had myocardial infarction = 1.7% of 22000 = (1.7/100)*22000

= 374 .

Thus, 374 physicians had myocardial infarction.

17) Number of physicians assigned to placebo group = Total number of physicians - Number of physicians assigned to low-dose aspirin group

= 22000 - 11000 = 11000

Thus, 11000 physicians were in the placebo group.

18) It is given that 97.8% of the physicians in the placebo group did not have a myocardial infarction.

Thus, number of physicians in the placebo group who did not have myocardial infarction = 97.8% of the number of physicians assigned to placebo group = 97.8% of 11000 = (97.8/100)*11000

= 10758 .

Thus, number of physicians in the placebo group who had a myocardial infarction

= 11000 - 10758 = 242

Thus, number of physicians in the placebo group who had myocardial infarction = 242

19) Number of physicians in the low-dose aspirin group who had myocardial infarction = (Number of physicians who had myocardial infarction) - (Number of physicians in the placebo group who had myocardial infarction) = 374 - 242 = 132

Thus, number of physicians on low-dose aspirin group who did not have a myocardial infarction = (Number of physicians who were assigned to low-dose aspirin) - (Number of physicians in the low-dose aspirin group who had myocardial infarction) = 11000 - 132 = 10868

Thus, number of physicians on low-dose aspirin who did not have a myocardial infarction = 10868 .