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In statistics, the matrix t-distribution (or matrix variate t-distribution) is the generalization of the multivariate t-distribution from vectors to matrices.〔Zhu, Shenghuo and Kai Yu and Yihong Gong (2007). ("Predictive Matrix-Variate ''t'' Models." ) In J.C. Platt, D. Koller, Y. Singer, and S. Roweis, editors, ''NIPS '07: Advances in Neural Information Processing Systems'' 20, pages 1721-1728. MIT Press, Cambridge, MA, 2008. The notation is changed a bit in this article for consistency with the matrix normal distribution article.〕 The matrix t-distribution shares the same relationship with the multivariate t-distribution that the matrix normal distribution shares with the multivariate normal distribution. For example, the matrix t-distribution is the compound distribution that results from sampling from a matrix normal distribution having sampled the covariance matrix of the matrix normal from an inverse Wishart distribution. In a Bayesian analysis of a multivariate linear regression model based on the matrix normal distribution, the matrix t-distribution is the posterior predictive distribution. ==Definition== |\boldsymbol\Sigma|^} : | cdf =No analytic expression| mean = if , else undefined| mode =| variance = if , else undefined| kurtosis =| entropy =| mgf =| char =see below| }} For a matrix t-distribution, the probability density function at the point of an space is : where the constant of integration ''K'' is given by : Here is the multivariate gamma function. The characteristic function and various other properties can be derived from the generalized matrix t-distribution (see below). 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「Matrix t-distribution」の詳細全文を読む スポンサード リンク
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