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) instead. Michael
-----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of SNN Sent: Mittwoch, 12. August 2009 00:34 To: r-help@r-project.org Subject: [R] Chi-squared approximation may be incorrect Hi, I am trying to run a Chi squre test but I am getting the following message Warning messages: 1: In chisq.test(t) : Chi-squared approximation may be incorrect Does anyone what it means? your help is appreciated -- View this message in context: http://www.nabble.com/Chi-squared-approximation-may-be-incorrect-tp24926 932p24926932.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
