TY - JOUR

T1 - Approximate sample size formulas for the two-sample trimmed mean test with unequal variances

AU - Luh, Wei Ming

AU - Guo, Jiin Huarng

PY - 2007/5

Y1 - 2007/5

N2 - Yuen's two-sample trimmed mean test statistic is one of the most robust methods to apply when variances are heterogeneous. The present study develops formulas for the sample size required for the test. The formulas are applicable for the cases of unequal variances, non-normality and unequal sample sizes. Given the specified a and the power (I - β), the minimum sample size needed by the proposed formulas under various conditions is less than is given by the conventional formulas. Moreover, given a specified size of sample calculated by the proposed formulas, simulation results show that Yuen's test can achieve statistical power which is generally superior to that of the approximate t test. A numerical example is provided.

AB - Yuen's two-sample trimmed mean test statistic is one of the most robust methods to apply when variances are heterogeneous. The present study develops formulas for the sample size required for the test. The formulas are applicable for the cases of unequal variances, non-normality and unequal sample sizes. Given the specified a and the power (I - β), the minimum sample size needed by the proposed formulas under various conditions is less than is given by the conventional formulas. Moreover, given a specified size of sample calculated by the proposed formulas, simulation results show that Yuen's test can achieve statistical power which is generally superior to that of the approximate t test. A numerical example is provided.

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U2 - 10.1348/000711006X100491

DO - 10.1348/000711006X100491

M3 - Article

C2 - 17535584

AN - SCOPUS:34249811792

VL - 60

SP - 137

EP - 146

JO - British Journal of Statistical Psychology

JF - British Journal of Statistical Psychology

SN - 0007-1102

IS - 1

ER -