1. In a wafer testing environment, a method of statistically comparing yields among two or more testers comprising the steps of: for a plurality of wafers comprising a lot, randomly dividing the lot among the two or more testers; for each of the two or more testers, determining yield statistics as a function of real-time wafer test yields and the number of wafer tests performed on the lot by each tester; and using the yield statistics, determining a univariate T-statistic for each tester for comparing the univariate T-statistic for each tester with a predetermined threshold statistical range.