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.: Home > Animal Science Papers and Reports > 2008 > Volume 26 Number 2 > H. Koknaroglu1*, C. Turan2, M. T. Toker1

Animal science application of robust tests: effect of zeolite and initial weight on fattening performance of cattle

H. Koknaroglu1*, C. Turan2, M. T. Toker1
1Department of Animal Science, Suleyman Demirel University, 32260 Isparta, Turkey 2Department of Biostatistics, Osmangazi University, 26480 Eskisehir, Turkey
Abstract :

literature search shows that robust techniques are rarely used in the animal sciences. Traditionally,
normal theory tests are used to determine whether there are significant differences among group
means. However, normal theory tests are optimal only if the distribution of error terms is normal
and in practice, non-normal distributions are more prevalent. Therefore, in this study, it is aimed
to present robust tests based on modified maximum likelihood (MML) estimators for testing the
equality of the group means. A real data set about the effect of zeolite and initial weight on feedlot performance of Brown Swiss cattle is the subject of the study. Results showed that the test statistics presented in this study are more powerful than the traditional normal-theory tests. They are also more robust against departures from assumed distribution and outliers.

Keywords :
Generalized logistic / non-normality / outliers / modified maximum likelihood / least squares / robustness

Date Deposited : 08 Aug 2011 10:16

Last Modified : 08 Aug 2011 10:16

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Volume 26, Number 2, - 2008

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