Question: A clinical trial examined the effectiveness of aspirin in the treatment of cerebral ischemia (stroke). Patients were randomized into treatment and control groups. The study was double-blind in the sense that neither the patients nor the physicians who evaluate the patients knew which patients received aspirin and which the placebo tablet. After 6 months of treatment, the attending physicians evaluated each patient’s progress as either favorable or unfavorable. Of the 78 patients in the aspirin group, 63 had favorable outcomes, 43 of the 77 control patients had favorable outcomes.

a. Compute the sample proportions of patients having favorable outcomes in the two groups

b. Give a 95% confidence interval for the difference between favorable proportions in the treatment and control group?

b. The physicians conducting the study had concluded from previous research that aspirin was likely to increase the chance of favorable outcome. Carry out a significance test to confirm this conclusion. State hypothesis, find the p-value and write a summary of your results.