Testing the Hardy-Weinberg law across strata

Summary The problem of testing the Hardy-Weinberg law when data are sampled from several populations with different allele frequencies is considered. An Odds-ratio representation of disequilibrium is proposed. This ration is assumed to be constant across strata, an assumption that seems more reasonalbe than that of previous authors of a constant difference in true and expected (undre equilibrium) heterozygote proportions. A score-type test which optimally combines information from the separate strata is then drived using the theory of unbiased estimating equations. Simulations show that the new test has greater power than previously proposed tests when the disequilibrium ratio is constant across strata. The method is applied to glyoxable genotype data form populations in India.