Hi,
The error is due to less than 5 observations in some cells. You can try, fisher.test(tabele) Fisher's Exact Test for Count Data data: tabele p-value = 0.0998 alternative hypothesis: two.sided A.K. ----- Original Message ----- From: Omphalodes Verna <omphalodes.ve...@yahoo.com> To: "r-help@r-project.org" <r-help@r-project.org> Cc: Sent: Tuesday, June 26, 2012 2:27 PM Subject: [R] chisq.test Dear list! I would like to calculate "chisq.test" on simple data set with 70 observations, but the output is ''Warning message:'' Warning message: In chisq.test(tabele) : Chi-squared approximation may be incorrect Here is an example: tabele <- matrix(c(11, 3, 3, 18, 3, 6, 5, 21), ncol = 4, byrow = TRUE) dimnames(tabela) <- list( "SEX" = c("M","F"), "HAIR" = c("Brown", "Black", "Red", "Blonde")) addmargins(tabele) prop.table(tabele) chisq.test(tabele) Please, give me an advice / suggestion / recommendation. Thanks a lot to all, OV [[alternative HTML version deleted]] ______________________________________________ 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.