(Revised 10/30/2009 - Also display results of uncorrected ("classical") calculation.)
Note: Before using this page for the first time, make sure you read the
JavaStat user interface guidelines for important
information about interacting with JavaStat pages.
Note: This page incorporates a continuity correction to the usual sample-size formula based on the normal approximation to the binomial distribution. This correction increases the sample size (for each group) by an amount approximately equal to 2/abs(p1-p2), where p1 and p2 are the population proportions for the two groups. For a good discussion of this, see: Statistical Methods for Rates and Proportions by Joseph L. Fleiss (2nd ed., 1981, John Wiley & Sons, NY), chapter 3. This web page produces values consistent with those in Table A3 of that book.