Kang et al. reported on a randomized trial of early surgery for patients with infective endocarditis (a heart infection). Of the 37 patients assigned to early surgery, 1 had a bad result (died, had an embolism, or had a recurrence of the problem within 6 months). Of the 39 patients with conventional treatment (of whom more than half had surgery later on), 11 had a bad result.
a. Find and compare the sample percentages of those who had a bad result for each group.
b. Create a two-way table with the labels Early Surgery and Conventional across the top.
c. Test the hypothesis that early treatment and a bad result are independent at the 0.05 level.
d. Does the treatment cause the effect? Why or why not?
e. Can you generalize to other people? Why or why not?