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arXiv 0711.0993math.STstat.APstat.TH
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变量选择后回归中置信区间最小覆盖概率的上界

Upper bounds on the minimum coverage probability of confidence intervals in regression after variable selection

Paul Kabaila, Khageswor Giri

摘要:

我们考虑一个线性回归模型,其中所关注的参数是回归参数向量的指定线性组合。我们假设,作为第一步,使用基于数据的模型选择(例如,通过初步假设检验或最小化AIC)来选择模型。通常的统计实践是,基于所选模型已先验地提供给我们的假设,为感兴趣的参数构建置信区间。该假设是错误的,并且其可导致具有较差覆盖属性的置信区间。我们提供了一个易于计算的有限样本上界(计算重复数值评估的二重积分),这个置信区间的最小覆盖概率。该界限适用于通过以下任何方法进行的模型选择:最小AIC、最小BIC、最大调整R平方、最小Mallow ' Cp和t检验。该上界的重要性在于,它描述了设计矩阵和模型选择程序的一般类别,对于这些设计矩阵和模型选择程序,该置信区间具有较差的覆盖特性。这个上界被证明是一个有限的样本模拟早期的大样本上界由于Kabaila和Leeb。

英文摘要:

We consider a linear regression model, with the parameter of interest a specified linear combination of the regression parameter vector. We suppose that, as a first step, a data-based model selection (e.g. by preliminary hypothesis tests or minimizing AIC) is used to select a model. It is common statistical practice to then construct a confidence interval for the parameter of interest based on the assumption that the selected model had been given to us a priori. This assumption is false and it can lead to a confidence interval with poor coverage properties. We provide an easily-computed finite sample upper bound (calculated by repeated numerical evaluation of a double integral) to the minimum coverage probability of this confidence interval. This bound applies for model selection by any of the following methods: minimum AIC, minimum BIC, maximum adjusted R-squared, minimum Mallows' Cp and t-tests. The importance of this upper bound is that it delineates general categories of design matrices and model selection procedures for which this confidence interval has poor coverage properties. This upper bound is shown to be a finite sample analogue of an earlier large sample upper bound due to Kabaila and Leeb.

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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