1.Pay attention to the width of the 95% confidence interval for the risk ratio and the odds ratio.

2.You will notice that unlike calculation of a 95% confidence interval for a mean difference, the 95% confidence interval for a risk ratio or odds ratio is not symmetric around the point estimate.

3.This is because the formulas for the confidence interval for the risk ratio and odds ratio are based on an exponential function, and because they have a lower bound of zero yet no upper bound.