A doctor released the results of clinical trials for a vaccine to prevent a particular disease. In these clinical trials, children were randomly divided in two groups. The subjects in group 1 (the experimental group) were given the vaccine, while the subjects in group 2 (the control group) were given a placebo. Of the children in the experimental group, developed the disease. Of the children in the control group, developed the disease. Complete parts (a) through (f) below.