how to use an unsplit variance in z-tests z-test to compare two proportions is how to use a unpooled variance test why use an unpooled z test what is the z-test for two proportions what are the limits for using unpooled variance what is z-test used for? z-test used to compare two proportions what is the z test for two proportions how to use unpooled variance what is the z test used to compare two proportions how to use unpooled variance z test definition how to find xp difference between two proportions the measure to compare two proportions is what is the z-test used for math which z-test is used to compare two proportions? z-test vs unpooled variance where does the unpooled variance come from when using an unpooled z test do you compare a proportion?