Online Program Home
  My Program

Abstract Details

Activity Number: 279 - Nonparametric Tests and Estimations for Clustered Data: It Is Essential for Non-Normal Data
Type: Topic Contributed
Date/Time: Tuesday, August 1, 2017 : 8:30 AM to 10:20 AM
Sponsor: International Chinese Statistical Association
Abstract #323394
Title: Incorporate Clustering Effects for the Wilcoxon Rank Sum Test: The Cluswilcox Command
Author(s): Xin He* and Jing Zhang and Mei-Ling Ting Lee and Bernard Rosner
Companies: University of Maryland, College Park and University of Maryland, College Park and University of Maryland and Harvard Medical School
Keywords: clustering effects ; cluswilcox ; Wilcoxon rank sum test ; stratum

Wilcoxon rank sum test, which assumes that individual sampling units are independent, is frequently used to compare measures of location when the underlying distributions are far from normal or not known in advance. However, in the presence of clustering effects, p-values will be underestimated and con fidence interval width will be too narrow if we still assume independence. Rosner et al. (2003) proposed a correction to the variance of the Wilcoxon rank sum statistic in order to account for clustering effects. In this talk, we introduce the cluswilcox Stata command, which incorporates the clustering effects for balanced (same number of subunits per cluster) and unbalanced (different number of subunits per cluster) data, strati ed (for important confounding variables) and non-strati ed data, in the presence or absence of tied rankings.

Authors who are presenting talks have a * after their name.

Back to the full JSM 2017 program

Copyright © American Statistical Association