The relationship between exercise and the risk of coronary heart disease

In a study investigating the relationship between exercise and the risk of coronary heart disease (CHD) among women, a cohort of healthy women (assuming no CHD at the beginning of the study) aged 35-60 were surveyed to ascertain the frequency of weekly exercise. The women were followed for 10 years. Investigators observed a total of 134 incident cases of CHD, 80 among women that reported exercising once per week, 21 among women that reported exercising twice per week, and the remainder in the group that reported no regular exercise over the study period. Person-years of observations for the exposure groups were as follows:  87,082 p-yrs for twice per week, 198,003 p-yrs for once per week, and 65,329 p-yrs for no exercise.

a. Set up the 2 x 3 table for analysis of this data.

b. Calculate the most appropriate measure of disease frequency for the exposure group