[R] Chi-squared approximation may be incorrect

Meyners, Michael, LAUSANNE, AppliedMathematics Michael.Meyners at rdls.nestle.com
Wed Aug 12 07:17:32 CEST 2009

Nancy (?),
see ?chisq.test (in particular the examples and the comment on "expected
frequency" there). 
A rule of thumb (see any basic text book) for the chisquared
approximation being okay is that the expected value in each cell is at
least 5. The warning tells you that this does not hold true for at least
one of your cells. 
You might want to try 
chisq.test(t, simulate.p.value = TRUE) 

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of SNN
Sent: Mittwoch, 12. August 2009 00:34
To: r-help at r-project.org
Subject: [R] Chi-squared approximation may be incorrect


I am trying to run a Chi squre test but I am getting the following

Warning messages:
1: In chisq.test(t) : Chi-squared approximation may be incorrect

Does anyone what it means?

your help is appreciated

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