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In statistics, the multivariate Behrens–Fisher problem is the problem of testing for the equality of means from two multivariate normal distributions when the covariance matrices are unknown and possibly not equal. Since this is a generalization of the univariate Behrens-Fisher problem, it inherits all of the difficulties that arise in the univariate problem. ==Notation and problem formulation== Let be independent random samples from two -variate normal distributions with unknown mean vectors and unknown dispersion matrices . The index refers to the first or second population, and the th observation from the th population is . The multivariate Behrens–Fisher problem is to test the null hypothesis that the means are equal versus the alternative of non-equality: : Define some statistics, which are used in the various attempts to solve the multivariate Behrens–Fisher problem, by : The sample means and sum-of-squares matrices are sufficient for the multivariate normal parameters , so it suffices to perform inference be based on just these statistics. The distributions of and are independent and are, respectively, multivariate normal and Wishart:〔 : 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Multivariate Behrens–Fisher problem」の詳細全文を読む スポンサード リンク
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