Exercise and Coronary Heart Disease In a study of women and coronary heart disease, the following sample results were obtained: Among 10,239 women with a low level of physical activity (less than 200 kcal wk), there were 101 cases of coronary heart disease. Among 9877 women with physical activity measured between 200 and 600 kcal wk, there were 56 cases of coronary heart disease (based on data from

“Physical Activity and Coronary Heart Disease in Women” by Lee, Rexrode, et al., Journal of the American Medical Association, Vol. 285, No. 11). Construct a 90%

confidence interval estimate for the difference between the two proportions. Does the difference appear to be substantial? Does it appear that physical activity corresponds to a lower rate of coronary heart disease?