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What hypotheses do "nonparametric" two-group tests actually test?

  • Ronan M. Conroy


    (Royal College of Surgeons in Ireland)

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    In this article, I discuss measures of effect size for two-group comparisons where data are not appropriately analyzed by least-squares methods. The Mann–Whitney test calculates a statistic that is a very useful measure of effect size, particularly suited to situations in which differences are measured on scales that either are ordinal or use arbitrary scale units. Both the difference in medians and the median difference between groups are also useful measures of effect size. Copyright 2012 by StataCorp LP.

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    Article provided by StataCorp LP in its journal Stata Journal.

    Volume (Year): 12 (2012)
    Issue (Month): 2 (June)
    Pages: 182–190

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    Handle: RePEc:tsj:stataj:v:12:y:2012:i:2:p:182-190
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    1. Roger Newson, 1998. "SOMERSD: Stata module to calculate Kendall's tau-a, Somers' D and median differences," Statistical Software Components S336401, Boston College Department of Economics, revised 06 May 2014.
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