Power analyses and sample size calculations are important parts of many research projects. Often, before data are even collected, it is necessary to calculate and justify the required sample size for ...

In epidemiologic studies and disease prevention trials, interest often involves estimation of the relationship between some disease endpoints and individual exposure. In some studies, due to the ...

When an effect size estimate from an earlier study is available, it is common practice to calculate a sample size for a future study by postulating that the true effect size equals the point estimate ...