1. A case-control study was performed to assess the relationship between oral contraceptive use and ovarian cancer. Results from this national study are given below.

Oral Contraceptive Use and Ovarian Cancer


OC Use


OC Use









a. What is the appropriate ratio measure of effect for these data? Calculate this measure.



b. Write a brief statement to interpret the measure of effect you calculated above.



2. OPENEPI OUTPUT NEEDED FOR PARTS OF THIS QUESTION: Consider the study presented in Q1 (Assume that there is no bias in the measure of effect for this study). Suppose a test of statistical significance is to be performed to determine whether the ratio measure of association in the population is significantly different from the null value of one. (Assume a 5% significance level)

a. State an appropriate null and alternative hypothesis.



b. Describe what a 5% significance level means in this study.



c. Using OpenEpi output, state the recommended chi-square value and its corresponding p-value or the Fisher’s exact p-value if appropriate.



d. How can you determine whether to reject or fail to reject the null hypothesis? Do you reject or fail to reject the null hypothesis in this study?



e. State a conclusion.



f. Report the 95% confidence interval for this measure of effect. Write a statement that interprets this confidence interval and comment about the precision of the point estimate.



g If the significance level had been 10% rather than 5%, would you reject or fail to reject the null hypothesis?