A prospective study was conducted to investigate the association of Major Coronary Heart Disease (CH D) and stress on the job on 2013 individuals. The contingency table is given below: Stress Major CHD Non Major CHD Total Yes 97 307 404 No 200 1409 1609 a. [1] Define explanatory and response variables 1:). [2] Estimate risk difference and construct 95% confidence interval for risk difference. c. [2] Estimate relative risk and construct 95% confidence interval for relative risk. d. [2] Estimate odds ratio and construct 95% confidence interval for odds ratio