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arXiv · 1306.5294

A Note on Computing Extreme Tail Probabilities of the Noncentral T Distribution with Large Noncentrality Parameter

Viktor Witkovsky
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Abstract

The noncentral $t$-distribution is a generalization of the Student's $t$-distribution. In this paper we suggest an alternative approach for computing the cumulative distribution function (CDF) of the noncentral $t$-distribution which is based on a direct numerical integration of a well behaved function. With a double-precision arithmetic, the algorithm provides highly precise and fast evaluation of the extreme tail probabilities of the noncentral $t$-distribution, even for large values of the noncentrality parameter $\delta$ and the degrees of freedom $\nu$. The implementation of the algorithm is available at the MATLAB Central, File Exchange: http://www.mathworks.com/matlabcentral/fileexchange/41790-nctcdfvw.

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Viktor Witkovsky. 2013-06-22. A Note on Computing Extreme Tail Probabilities of the Noncentral T Distribution with Large Noncentrality Parameter. https://arxiv.org/abs/1306.5294

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