Suppose that an investigation of the association between regular physical activity and ovarian cancer revealed that the incidence rate of ovarian cancer among women who engaged in regular physical activity was 30 per 100,000 woman-years of follow-up, whereas the rate among women who did not engage in regular activity was 45 per 100,000 woman-years of follow-up.

1. Use these data to compute the incidence rate ratio of ovarian cancer for women who are physically active versus women who are not.

2.. State in words your interpretation of this measure.

3. Compute the incidence rate difference of ovarian cancer for women who are physically active versus women who are not.

4. State in words your interpretation of this measure.

5. If there were no association between regular physical activity and ovarian cancer, what would be the numeric values of the incidence rate ratio and incidence rate difference?