I would also review: Chi-squared and Fisher-Irwin tests of two-by-two tables with small sample recommendations Ian Campbell Stat in Med 26:3661-3675; 2007 http://www3.interscience.wiley.com/cgi-bin/abstract/114125487/ABSTRACT
and the bottom Frank Harrell's page here: http://biostat.mc.vanderbilt.edu/twiki/bin/view/Main/DataAnalysisDisc where he has some comments on the above. HTH, Marc Schwartz Simon Blomberg wrote: > Why do people automatically jump to Fisher's Exact test? That test > conditions on BOTH marginal row totals. Usual contingency table analyses > condition on one margin, at most. You should look very carefully at the > underlying model for your data. Fisher's Exact test might not be > appropriate. Agresti's "Categorical Data Analysis" has a good discussion > of this. > > Simon. > > On Tue, 2008-01-15 at 21:49 -0500, My Coyne wrote: >> Thank you for your help; I will try fisher.test(). >> >> >> >> >> >> From: anna freni sterrantino [mailto:[EMAIL PROTECTED] >> Sent: Tuesday, January 15, 2008 8:53 PM >> To: [EMAIL PROTECTED]; [EMAIL PROTECTED] >> Subject: Re: [R] In chisq.test(x) : Chi-squared approximation may be >> incorrect >> >> >> >> Hi! >> the warning you got >> "Chi-squared approximation may be incorrect" >> is because probably there are less than 5 observations in >> the cell. Maybe will help to >> try fisher.test() >> >> Cheers >> >> Anna >> >> >> >> >> >> >> >> >> ----- Messaggio originale ----- >> Da: My Coyne<[EMAIL PROTECTED]> >> A: [EMAIL PROTECTED] >> Inviato: Lunedì 14 gennaio 2008, 21:51:30 >> Oggetto: [R] In chisq.test(x) : Chi-squared approximation may be incorrect >> >> Hello, >> >> >> >> I received the following warning when running chi-square; >> >> n Is there a way to catch the 'error' code of 'warning' after run >> chisq.test(x)? >> >> n What does this error mean? >> >> >> >> Thank you for your help. >> ______________________________________________ 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.
