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Limit laws for multivariate skewness in the sense of Móri, Rohatgi and Székely. (English) Zbl 0902.62060

Summary: Let \(X\) be a \(d\)-dimensional random vector having zero expectation and unit covariance matrix. T. F. Móri, V. K. Rohatgi and G. J. Székely [Theor. Probab. Appl. 38, No. 3, 547-551 (1993; Zbl 0807.60020)] proposed and studied \(\widetilde{\beta}_{1,d}= \| E(\| X\|^2 X)\|^2\) as a population measure of multivariate skewness. We derive the limit distribution of an affine invariant sample counterpart \(\widetilde{b}_{1,d}\) of \(\widetilde{\beta}_{1,d}\). If the distribution of \(X\) is spherically symmetric, this limit law is \(\lambda\chi_d^2\), where \(\lambda\) depends on \(E\| X\|^4\) and \(E\| X\|^6\). In case of spherical (elliptical) symmetry, we also obtain the asymptotic correlation between \(\widetilde{b}_{1,d}\) and K. V. Mardia’s [Biometrika 57, 519-530 (1970; Zbl 0214.46302)] time-honoured measure of multivariate skewness. If \(\widetilde{\beta}_{1,d}>0\), the limit distribution of \(n^{1/2} (\widetilde{b}_{1,d}- \widetilde{\beta}_{1,d})\) is normal. Our results reveal the deficiencies of a test for multivariate normality based on \(\widetilde{b}_{1,d}\).

MSC:

62H10 Multivariate distribution of statistics
62E20 Asymptotic distribution theory in statistics
62H05 Characterization and structure theory for multivariate probability distributions; copulas
62A01 Foundations and philosophical topics in statistics
62H15 Hypothesis testing in multivariate analysis
60F05 Central limit and other weak theorems
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References:

[1] Baringhaus, L.; Henze, N., Limit distributions for Mardia’s measure of multivariate skewness, Ann. Statist., 20, 1889-1902 (1992) · Zbl 0767.62041
[2] Bera, A.; John, S., Tests for multivariate normality with Pearson alternatives, Commun. Statist. Theory Methods, 12, 103-117 (1983)
[3] Eaton, M. L.; Perlman, M. D., The nonsingularity of generalized sample covariance matrices, Ann. Statist., 1, 710-717 (1973) · Zbl 0261.62037
[4] Erdély, A.; Magnus, W.; Oberhettinger, F.; Tricomi, F. G., (Higher Transcendental Functions, Vol. 2 (1953), McGraw-Hill: McGraw-Hill New York) · Zbl 0052.29502
[5] Fang, K. T.; Kotz, S.; Ng, K. W., Symmetric Multivariate and Related Distributions (1989), Chapman & Hall: Chapman & Hall London
[6] Gastwirth, J. L.; Owens, M. E.B., On classical tests of normality, Biometrika, 64, 135-139 (1977) · Zbl 0389.62014
[7] Gregory, G. G., Large sample theory for U-statistics and tests of fit, Ann. Statist., 5, 110-123 (1977) · Zbl 0371.62033
[8] Horswell, R. L.; Looney, St. W., A comparison of tests for multivariate normality that are based on measures of multivariate skewness and kurtosis, J. Statist. Comput. Simul., 42, 21-38 (1992)
[9] Mardia, K. V., Measures of multivariate skewness and kurtosis with applications, Biometrika, 57, 519-530 (1970) · Zbl 0214.46302
[10] Móri, T. F.; Rohatgi, V. K.; Székely, G. J., On multivariate skewness and kurtosis, Theoret. Probab. Appl., 38, 547-551 (1993) · Zbl 0807.60020
[11] Okamoto, M., Distinctness of the eigenvalues of a quadratic form in a multivariate sample, Ann. Statist., 1, 763-765 (1973) · Zbl 0261.62043
[12] Schwager, S. J., Multivariate Skewness and Kurtosis, (Encyclopedia of Statistical Sciences, Vol. 6 (1985), Wiley: Wiley New York), 122-125
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