The following data were collected from a cohort study that examined a possible association between prior pregnancy and ovarian cancer in a high-risk group of women. pregnancy ovarian cancer Yes No Total Yes 56 544 600 No 44 306 350 Total 100 850 950 a) Calculate the appropriate measure of frequency of ovarian cancer for. i. The exposed women (2 marks) The unexposed women (2 marks) All women (2 marks) Interpret your results for i - i together. (2 mark) ii. 111. iv. b) Calculate relative risk and interpret your answer. (5 marks) c) Can the odds ratio be an approximate estimate of relative risk in this study context? Justify your answer. (3 marks)