I am looking for an Excel function or a formula that will give me the p-value for an F-test comparing the variances of two populations. I can get the p-value using the "F-Test Two-Sample for Variances" tool in the Data Analysis Tool Pak, but I cannot find the p-value formula behind the tool. I use the CHISQ.DIST.RT function for single-variance problems, but I do not see how I can use it when comparing two variances, with two different degrees of freedom. Any ideas would be greatly appreciated. Thanks.