There is an error in reference 7. The correct reference is Taeger D, Sun T, Keil U, Straif K. A stand-alone window application for computing exact person-years, standardized mortality ratios and confidence intervals in epidemiologic studies. Epidemiology 2000;11:607–608.In the Methods section, there is an error in the equation in the section titled "Statistical Analysis." The formula is incorrect. Please view the complete, correct formulas and added text here:Where X is a Poisson random variable with parameter μ of the Poisson distribution, x is a observed value of X, and μ
and μ
are the values of the lower confidence limit and upper confidence limit of μ respectively, and the α is 0.05 at 95% CI.A reference is omitted from the last sentence of the first paragraph under the subheading "Statistical Analysis" in the Methods section. The sentence should read: In theory, confidence interval is expressed as following equation at 95% CI (Sahai et al., 1993). The reference is: Sahai H, Khurshid A. Confidence intervals for the mean of a Poisson distribution: A review. Biom J. 1993;35:857–867.