Journal ArticleDOI
Three Multiple Comparison Procedures for Trimmed Means
TLDR
In this paper, the authors compare three different comparison procedures and compare them to two methods for comparing means, i.e., the trimmed mean and the sample mean, which is a measure of location having a standard error that is relatively unaffected by heavy tails and outliers.Abstract:
Two common goals when choosing a method for performing all pairwise comparisons of J independent groups are controlling experiment wise Type I error and maximizing power. Typically groups are compared in terms of their means, but it has been known for over 30 years that the power of these methods becomes highly unsatisfactory under slight departures from normality toward heavy-tailed distributions. An approach to this problem, well-known in the statistical literature, is to replace the sample mean with a measure of location having a standard error that is relatively unaffected by heavy tails and outliers. One possibility is to use the trimmed mean. This paper describes three such multiple comparison procedures and compares them to two methods for comparing means.read more
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Reference EntryDOI
Multiple Comparison Procedures
TL;DR: In this paper, the authors discuss MCPs that can be used to investigate simple pairwise differences between treatment group means, as well as complex comparisons (i.e., nonpairwise comparisons) between treatment groups means.
Journal ArticleDOI
Statistical Inference Based on Ranks
Journal ArticleDOI
Heterogeneity of variance in clinical data.
TL;DR: No one robust method is ideal for all situations, but such methods are superior to the traditional tests and should be widely used to control rate of Type I error and maintain power.
Journal ArticleDOI
ANOVA: A Paradigm for Low Power and Misleading Measures of Effect Size?
TL;DR: There are many robust and exploratory ways of comparing groups that can reveal important differences that are missed by conventional methods based on means, and even modern methods based solely on robust measures of location.
Journal ArticleDOI
To Trim or Not To Trim: Tests of Location Equality under Heteroscedasticity and Nonnormality.
Lisa M. Lix,H. J. Keselman +1 more
TL;DR: In this article, the authors compared the performance of the mean equality tests proposed by Alexander and Govern, Box, Brown and Forsythe, James, and Welch, as well as the analysis of variance F test, for their ability to limit the number of Type I errors and to detect true treatment group differences in one-way, completely randomized designs in which the underlying distributions were nonnormal, variances were nonhomogeneous, and groups sizes were unequal.
References
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Book
Multiple Comparison Procedures
Yosef Hochberg,Ajit C. Tamhane +1 more
TL;DR: In this article, a theory of multiple comparison problems is presented, along with a procedure for pairwise and more general comparisons among all treatments among all the treatments in a clinical trial.
Journal ArticleDOI
On closed testing procedures with special reference to ordered analysis of variance
Journal ArticleDOI
Pairwise Multiple Comparison Procedures with Unequal N's and/or Variances: A Monte Carlo Study.
Paul A. Games,John F. Howell +1 more
TL;DR: In this article, three different methods for testing all pairs of y − k, - y - k were compared under varying sample size (n) and variance conditions, with unequal n's of six and up.