Hi R Masters! I will make a populational survey in my hospital. Using the program I calculated the sample size for disease proportion in population. --------------- pop<-2400 p<-.2 d<-.05 alpha<-.05 z<-qnorm(1-alpha/2) n<-z^2*(p*(1-p))/d^2 sample<-n/(1+(n/pop)) sample --------------- Well, do I know the sample size for this study, but is it possible to do an power analysis for this study using the R? Thanks in advance Bernardo Rangel Tura, MD, MSc National Institute of Cardiology Laranjeiras Rio de Janeiro Brazil