Relative Risk and Odds Ratio In a clinical trial of 734 subjects treated with Viagra, 117 reported headaches. In a control group of 725 subjects not treated with Viagra, 29 reported headaches. Denoting the proportion of headaches in the treatment group by pt and denoting the proportion of headaches in the control group by pc, the relative risk is pt pc. The relative risk is a measure of the strength of the effect of the Viagra treatment. Another such measure is the odds ratio, which is the ratio of the odds in favor of a headache for the treatment group to the odds in favor of a headache for the control group, found by evaluating the following:

The relative risk and odds ratios are commonly used in medicine and epidemiological studies. Find the relative risk and odds ratio for the headache data.