What's the score?
If you have calculated a confidence interval for an infection rate and found the interval extending into meaningless negative numbers, chances are the error is due to use of approximation formulae. Many of us unknowingly were taught to use the Wald approximation, which does not always approximate the exact binomial distribution accurately. Poor approximation can occur in infection surveillance at both small and large sample sizes.
Birnbaum
D
D
Applied Epidemiology, Sidney, British Columbia, Canada.
D003428:Cross Infection / Q000453:epidemiology*; D003627:Data Interpretation, Statistical; D006801:Humans; D017053:Infection Control / Q000706:statistics & numerical data*; D018401:Sample Size; D018571:Sentinel Surveillance