In randomized, double-blind clinical trials of a new vaccine, rats were randomly divided into two groups. Subjects in group 1
received the new vaccine while subjects in group 2 received a control vaccine. After the second dose, 104 of 669 subjects in the experimental group (group 1) experienced drowsiness as a side effect. After the second dose, 61 of 550 of the subjects in the control group (group 2) experienced drowsiness as a side effect. Does the evidence suggest that a higher proportion of subjects in group 1 experienced drowsiness as a side effect than subjects in group 2 at the α=0.10 level of significance?
