And probably why chisq.test has the rescale.p= argument. Your second problem with small expected values can be handled with simulate.p.value=.
> chisq.test(f, p=p11) Error in chisq.test(f, p = p11) : probabilities must sum to 1. > 1-sum(p11) [1] 4.3036e-08 > chisq.test(f, p=p11, rescale.p=TRUE) Chi-squared test for given probabilities data: f X-squared = 7.6268, df = 14, p-value = 0.9078 Warning message: In chisq.test(f, p = p11, rescale.p = TRUE) : Chi-squared approximation may be incorrect > chisq.test(f, p=p11, rescale.p=TRUE, simulate.p.value=TRUE) Chi-squared test for given probabilities with simulated p-value (based on 2000 replicates) data: f X-squared = 7.6268, df = NA, p-value = 0.7996 ------------------------------------- David L Carlson Department of Anthropology Texas A&M University College Station, TX 77840-4352 -----Original Message----- From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Berend Hasselman Sent: Friday, February 20, 2015 12:13 PM To: pari hesabi Cc: r-help@r-project.org Subject: Re: [R] Chi-square test > On 20-02-2015, at 19:05, pari hesabi <statistic...@hotmail.com> wrote: > > Hello, > If the vector of observed frequencies is: > f<-c(0,0,0,2,3,6,17,15,21,21,14,10,5,1,5) > and the vector of probability :p11<-c(7.577864e-06, 1.999541e-04 > ,1.833510e-03, 9.059845e-03, 2.886977e-02, 6.546229e-02 ,1.124083e-01, > 1.525880e-01, 1.689712e-01, 1.563522e-01, 1.232031e-01, 8.395000e-02, > 5.009534e-02, 2.645857e-02,0.0205403) > The sum of the probabilities is equal to one. But when I want to do the the > Chi-square test, I get this error: probabilities must sum to one. print sum(p11)-1 > Does anybody know the reason? R FAQ 7.31 (http://cran.r-project.org/doc/FAQ/R-FAQ.html) Berend > Best Regards, > pari > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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 -- To UNSUBSCRIBE and more, see 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 -- To UNSUBSCRIBE and more, see 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.