D+ D- D+ D- E 500 3000 E 650 2850 E 250 3250 E 200 3300 a. What is the most appropriate measure of association for this study? b. Using this measure of association, does age modify the association between contact lens use and eye infection? Why or why not? (If age is an effect modifier, then stop after answering part b. If age is not an effect modifier, then continue with parts c and d.) c. If age is not an effect modifier, does age confound the association between contact lens use and eye infection? Why or why not? d. If age is not an effect modifier, show how age either meets or does not meet each of the criteria for confounding