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Four improved statistics for contrasting means by correcting skewness and kurtosis
Hirokazu Yanagihara1, Ke-Hai Yuan
1Department of Social Systems and Management, Graduate School of Systems and Information Engineering, University of Tsukuba, Japan.
Abstract:
This paper is concerned with removing the influence of non-normality in the classical t-statistic for contrasting means. Using higher-order expansion to quantify the effect of non-normality, four corrected statistics are provided. Two aim to correct the mean bias and two to correct the overall distribution. The classical t-statistic is also robust against non-normality when the observed variables satisfy certain structures. A special case is when the marginal distributions of the contrast are independent and identically distributed.
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