A Swedish study considered the effect of low-dose aspirin on reducing the risk of stroke and heart attacks among people who have already suffered a stroke. This study was published in a leading medical journal called "Lancet". Of 1360 patients, 676 were randomly assigned to the aspirin treatment (one low-dose tablet a day) and remaining to a placebo treatment. During a follow-up period averaging three years, the number of deaths due to Myocardial Infarction were 18 for the aspirin group and 28 for the placebo group.
a) Calculate and interpret the relative risk of death, and the odds ratio.
b) Conduct an inferential analysis for these data (use 95% confidence intervals for both RR and OR). Interpret these results.