A Robust Alternative to the t - Test

Zahayu Md Yusof, Suhaida Abdullah, Sharipah Soaad Syed Yahaya, Abdul Rahman Othman

Abstract


t-test is a classical test statistics for testing the equality of two groups. However, this test is very sensitive to non-normality as well as variance heterogeneity. To overcome these problems, robust method such as Ft and S1 tests statistics can be used. This study proposed the use of a robust estimator that is trimmed mean as the central tendency measure in Ft test and median as the central tendency measure in S1 test when comparing the equality of two groups. The performance of the S1 test with MADn was able to give the most convincing result than the other methods. The Ftwith MADn showed comparable results with the conventional methods. This study has shown some improvement in the statistical solution of detecting differences between location parameters. These modified methods may serve as alternatives to some other robust statistical methods which are unable to handle either the problem of non-normality, variance heterogeneity or unbalanced design.


Full Text: PDF DOI: 10.5539/mas.v6n5p27

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Modern Applied Science   ISSN 1913-1844 (Print)   ISSN 1913-1852 (Online)

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