The Robust Test Statistic in Comparing Two Independent Groups using Trimming and Winsorization

The classical independent t-test is often in jeopardy when the assumptions of normality or homogeneity of variances being violated. The test performs worsen when these violations occur simultaneously. Alexander-Govern test offers the alternative solution to the classical t-test when dealing with het...

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Detalles Bibliográficos
Main Authors: Abdullah, Suhaida, Syed Yahaya, Sharipah Soaad, Md Yusof, Zahayu
Formato: Artigo
Idioma:English
Publicado: IJENS Publisher, Rawalpindi, Pakistan 2017
Subjects:
Acceso en liña:https://repo.uum.edu.my/id/eprint/30956/1/IJBAS%2017%2006%202017%2001-06.pdf
Descripción
Summary:The classical independent t-test is often in jeopardy when the assumptions of normality or homogeneity of variances being violated. The test performs worsen when these violations occur simultaneously. Alexander-Govern test offers the alternative solution to the classical t-test when dealing with heterogeneous variances conditions. However, it produces good control of Type I error rates only if the data are normally distributed, which is a known fact that normality is hardly achieved in real life situation. As a remedy, in this study, we modify the Alexander-Govern test using trimmed mean and Winsorized mean as the location measures. Generally, the modified test using trimmed mean performs better compared to the original test in terms of Type I error rates. However, the test using Winsorized mean failed to control the Type I error rate well under most condition considered