| Date: | Thu, 1 Jul 2004 19:20:50 +0200 |
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| Reply-To: | Marta García-Granero
<biostatistics@terra.es> |
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| Sender: | "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU> |
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| From: | Marta García-Granero
<biostatistics@terra.es> |
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| Organization: | Asesoría Bioestadística |
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| Subject: | Re: Brown-Forsythe and Welch |
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| In-Reply-To: | <s0e4406c.033@MAINCF1P.cf.ac.uk> |
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| Content-Type: | text/plain; charset=ISO-8859-15 |
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Hi Paul,
PM> I have a user who has done a OneWay Anova and the variances are shown to be
PM> unequal, she then obtains the Robust Test for Equality of Means (Welch and
PM> Brown-Forsythe).
To my knowledge (sorry, no refs at hand):
Under normality and variance heterogeneity, the Brown-Forsythe and the
Welch test perform well over a wide range of parameter configura-
tions, but the Welch test becomes liberal when the sample sizes are
small and the number of groups is large.
I downloaded a copy of an article I found useful:
http://www.sfb475.uni-dortmund.de/berichte/tr32-01.ps
Regards
Marta Garcia-Granero, PhD
Statistitian
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