Reference no: EM132854909
The Physician's Health Study: Lawrence Craven, a California general practitioner, noticed that aspirin somehow prevented blood from clotting in his pa- tients and hypothesized that aspirin might help prevent heart attacks caused by clots in coronary arteries. So he started prescribing aspirin to several thousand patients. In this famous experiment, a team of investigators were interested in testing whether aspirin prevents myocardial infarctions (heart attacks) and other cardiovascular events. Male physicians between 40 and 84 years old were randomly assigned to take an aspirin (a drug used for pain relief) or a placebo (a sugar pill with no medicine in it) every day. They were then followed and the number of myocardial infarctions in each group was recorded.
There were several other variables measured, but we are focussing on only some of them in this question. The data are summarized in the table below:
Myocardial Infarction No Myocardial Infarction Total
Placebo 189 10,845 11,034
Aspirin 104 10,933 11,037
Total 293 21,778 22,071
Answer on the information given above. Do not refer to the full study by finding it from another resource.
(a) Consider the parameter(s) of interest in this study.
- Label the appropriate parameter(s) of interest and write out what they are in plain English. Use proper statistical notation and an appropriate subscript to denote each population. Then, describe what the parameter(s) represent in terms of the study.
- State the question of interest in terms of the parameters (using a mathematical relationship) and explain your reasoning.
(b) Fill in the blanks below with the correct numerical values.
(i) The sample size is ---------------------- .
(ii) -------------- male physicians in this study took aspirin.
(iii)--------------- % of male physicians took a placebo and suffered a heart attack.
(iv)--------------- % of male physicians suffered from a heart attack.
(v)---------------- % of male physicians who suffered from a heart attack took a placebo.
Highlight/underline the numerical values
(c) What do you think the population of interest is? Use only the information given above to answer this question - do not read the full study. Do you think the sample is representative of the population? Answer 'Yes' or 'No' and then justify.
(d) Give a reasonable explanation for why the investigators chose physicians as the sampled patients?
(e) If the statistical analysis shows that the percentage of myocardial infarctions for aspirin users is significantly lower than the percentage of myocardial infarctions for placebo users, can we conclude that aspirin prevents heart attacks? Answer 'Yes' or 'No' and then give justification. (not being asked any kind of statistical analysis here.)