Epidemiology: Please help with answering.

Measures of association The table below shows data from a study of oral contraceptive use in relation to development of bacteriumia. Calculate the Risk Difference from this table. Your answer should be in per 100000 cases Bacteriumia No bacteriumia Total Oral contraceptive use 27 455 482 No oral contraceptive use 77 1831 1908 Total 104 2286 2390 Calculate the crude mortality rates for populations A and B. Which population appears healthier? Population A Population B Age Deaths Population Rate (A) Deaths Population Rate (B) (yrs) (size) 0-4 80 22,000 400 100,000 5-19 97 85,000 340 290,000 20-44 140 100,000 300 300,000 45-64 350 70,000 850 170,000 65+ 600 31,000 1,400 80,000 Total 1,267 308,000 3,290 940,000