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arXiv 2209.09495math.PR
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多元正态随机向量函数Stein方法的改进界

Improved bounds in Stein's method for functions of multivariate normal random vectors

Robert E. Gaunt, Heather Sutcliffe

摘要:

在最近的一篇论文中,Gaunt 2020扩展了Stein的方法,以限制可以表示为中心多元正态随机向量$Σ^{1/2}\mathbf{Z}$的函数$g:\mathbb{R}^d\rightarrow\mathbb{R}$的分布,其中$\mathbf{Z}$是标准$d$维多元正态随机向量,$Σ$是非负定协方差矩阵。本文在较弱的矩条件、较小的常数和较简单的形式的意义下,对$g$具有多项式增长的导数的情形,得到了改进的界.我们获得新的非均匀边界的斯坦因方程的解的衍生物,并使用这些不等式,以获得一般的距离上的界限,测量使用光滑的测试功能,$g(\mathbf{W}_n)$和$g(\mathbf{Z})$的分布之间,其中$\mathbf{W}_n$是一个标准化的总和随机向量与独立组件和$\mathbf{Z}$是一个标准的$d$维多元正态随机向量。我们应用这些一般的界限,以获得的卡方近似的家庭的权力分歧统计(特殊情况下,包括皮尔逊和似然比统计),对于两个细胞分类的情况下,在文献中现有的结果,提高了界限。

英文摘要:

In a recent paper, Gaunt 2020 extended Stein's method to limit distributions that can be represented as a function $g:\mathbb{R}^d\rightarrow\mathbb{R}$ of a centered multivariate normal random vector $Σ^{1/2}\mathbf{Z}$ with $\mathbf{Z}$ a standard $d$-dimensional multivariate normal random vector and $Σ$ a non-negative definite covariance matrix. In this paper, we obtain improved bounds, in the sense of weaker moment conditions, smaller constants and simpler forms, for the case that $g$ has derivatives with polynomial growth. We obtain new non-uniform bounds for the derivatives of the solution of the Stein equation and use these inequalities to obtain general bounds on the distance, measured using smooth test functions, between the distributions of $g(\mathbf{W}_n)$ and $g(\mathbf{Z})$, where $\mathbf{W}_n$ is a standardised sum of random vectors with independent components and $\mathbf{Z}$ is a standard $d$-dimensional multivariate normal random vector. We apply these general bounds to obtain bounds for the chi-square approximation of the family of power divergence statistics (special cases include the Pearson and likelihood ratio statistics), for the case of two cell classifications, that improve on existing results in the literature.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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