Accounting Assume that the annual incidence rate for breast cancer among those exposed to oral oral contraceptives is 4.4 per 10,000, and among those not exposed is 2.2 per 10,000. a. How large a sample size must be studied in order to detect this difference in risk in one year? (Assume that equal numbers of exposed and unexposed individuals are studied.) b. How large must the sample be if the study is to last for 10 years? d. A case-control study of the same problem is planned using cases and an equal number of unmatched controls. Again, the risk for breast cancer is assumed to be twice as great among those exposed to oral contraceptives as among those not exposed. If 25% of women in the general population are exposed to oral contraceptives then how many cases and controls will be needed e. What would the corresponding number be if only 10% of women in the general population were exposed?