$\text{95% confidence limits for a Rate Ratio}={e}^{\left(\mathrm{ln}\left(RR\right)±1.96\sqrt{\frac{1}{\text{a}}+\frac{1}{\text{b}}}\right)}$

Description:

Math equation. The 95% confidence limits for a rate ratio equal the constant "e" raised to the power of natural log of the rate ratio plus or minus 1.96 times the square root of the sum of 1 over a plus 1 over b where a equals the number of events in the exposed group and b equals the number of events in the unexposed group.