Title

Stepwise Multiple Tests For Successive Comparisons Of Treatment Effects

Keywords

Critical constants; Familywise error rate; Multiple comparisons; Multivariate-t distribution; Simultaneous confidence intervals

Abstract

Suppose that the k treatments under comparison are ordered in a certain way. For example, they may be a sequence of increasing dose levels of a drug. It is interesting to look directly at the successive differences between the treatment effects μi's, namely the set of differences μ2 - μ1,μ3 - μ2,...,μk - μk-1. Lee and Spurrier (J. Statist. Plann. Inference 43 (1995) 323) propose a one- sided and a two-sided simultaneous confidence interval procedures for making successive comparisons between treatments. In this paper we develop step-down and step-up tests for testing the families of hypotheses Hi0 : μi+1 - μi = 0 vs Hia : μi+1 - μi > 0, i = 1,...,k - 1 (one-sided alternatives) Hi0 : μi+1 - μi = 0 vs Hia : μi+1 - μi ≠ 0, i = 1,...,k - 1 (two-sided alternatives) These stepwise tests are uniformly more powerful than the simultaneous confidence interval procedures in terms of rejection of the null hypotheses, though the simultaneous confidence interval procedures provide information on the magnitudes of the μ i+1 - μi's. The critical constants required for applying these multiple tests are provided, and the tests are illustrated with a numerical example. © 2003 Published by Elsevier B.V.

Publication Date

5-28-2004

Publication Title

Computational Statistics and Data Analysis

Volume

46

Issue

1

Number of Pages

189-199

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1016/S0167-9473(03)00137-3

Socpus ID

2142648774 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/2142648774

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