TESTING A GENETIC EQUILIBRIUM ACROSS STRATA

A score statistic for testing the Hardy-Weinberg law for data sampled from several populations with different allele frequencies is derived assuming a common coefficient of disequilibrium (odds ratio-type) acro ss strata. The assumption can be examined by a chi-square goodness-of- fit test. It is unlikely such a model would be rejected in typical stu dies involving human populations. Under this model, a Wald-type test h as substantially less power than the score test. hn approximate formul a for the sample size required for a specific power of the st ratified score test for detecting departure from equilibrium is given.