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Robustness and power of tests of variability on two independent groups
Author(s) -
Ramsey Philip H.,
Brailsford Eric A.
Publication year - 1990
Publication title -
british journal of mathematical and statistical psychology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.157
H-Index - 51
eISSN - 2044-8317
pISSN - 0007-1102
DOI - 10.1111/j.2044-8317.1990.tb00929.x
Subject(s) - kurtosis , mathematics , statistics , robustness (evolution) , sample size determination , sample (material) , population mean , population , statistical power , econometrics , demography , biochemistry , chemistry , chromatography , estimator , sociology , gene
A number of procedures are investigated for testing differences in variability in seven population distributions. Some procedures, previously considered robust, are found to be robust only with certain sample sizes. Testing for kurtosis is found to be useful for increasing power provided N > 60. For equal sample sizes, maximum power is found to result from the application of one of Levene's procedures with platykurtic distributions and the Brown‐Forsythe procedure with leptokurtic distributions. No procedure is found to be adequately robust for all populations with unequal sample sizes. However, several methods are determined to be adequate if run at half the nominal alpha level.