Abstract
We consider computational methods for evaluating and approximating multivariate chi-square probabilities in cases where the pertaining correlation matrix or blocks thereof have a low factorial representation. To this end, techniques from matrix factorization and probability theory are applied. We outline a variety of statistical applications of multivariate chi-square distributions and provide a system of MATLAB programs implementing the proposed algorithms. Computer simulations demonstrate the accuracy and the computational efficiency of our methods in comparison with Monte Carlo approximations, and a real data example from statistical genetics illustrates their usage in practice.
Acknowledgements
We are grateful to an anonymous referee for constructive comments which improved the presentation. We thank Thomas Royen for many valuable comments, especially regarding Remark 3.7.
Disclosure statement
No potential conflict of interest was reported by the authors.