In clinical tests of adverse reactions to the drug Viagra, 7% of the 734 subjects in the treatment group experienced dyspepsia (indigestion), but 2% of the 725 subjects in the placebo group experienced dyspepsia (based on data from Pfizer Pharmaceuticals).
a. Is there sufficient evidence to support the claim that dyspepsia occurs at a higher rate among Viagra users than those who do not use Viagra?
b. Construct a 95% confidence interval estimate of the difference between the dyspepsia rate for Viagra users and the dyspepsia rate for those who use a placebo. Do the confidence interval limits contain 0, and what does this suggest about the two dyspepsia rates?