You should probably read up on what the chi-squared test actually tests: in one form, it asks whether some set of observations could have come from a given multinomial distribution. Concretely, it asks whether it is "reasonable" to get 3 blues, 4 reds, and 2 whites from a uniform distribution over read white and blue. (Real statisticians will have all sorts of problems with that over-simplification) What you seem to be asking is whether it is "reasonable" to get 3 blues 4 reds, 2 whites, and 6 greens from a uniform distribution over red white and blue -- obviously something doesn't fit here. Caveat: if matrix1 matches matrix2 but there were null observations that got dropped, then this can be done.
https://en.wikipedia.org/wiki/Pearson%27s_chi-squared_test The website http://stats.stackexchange.com/ can (and will) provide more statistically oriented help. Michael On Fri, Mar 9, 2012 at 11:46 AM, aoife doherty <[email protected]> wrote: > Thank you. Can the chi-squared test compare two matrices that are not the > same size, eg if matrix 1 is a 2 X 4 table, and matrix 2 is a 3 X 5 matrix? > > > On Fri, Mar 9, 2012 at 4:37 PM, Greg Snow <[email protected]> wrote: > >> The chi-squared test is one option (and seems reasonable to me if it >> the the proportions/patterns that you want to test). One way to do >> the test is to combine your 2 matrices into a 3 dimensional array (the >> abind package may help here) and test using the loglin function. >> >> On Thu, Mar 8, 2012 at 5:46 AM, aaral singh <[email protected]> wrote: >> > Hi.Please help if someone can. >> > >> > Problem: >> > I have 2 matrices >> > >> > Eg >> > >> > matrix 1: >> > Freq None Some >> > Heavy 3 2 5 >> > Never 8 13 8 >> > Occas 1 4 4 >> > Regul 9 5 7 >> > >> > matrix 2: >> > Freq None Some >> > Heavy 7 1 3 >> > Never 87 18 84 >> > Occas 12 3 4 >> > Regul 9 1 7 >> > >> > >> > I want to see if matrix 1 is significantly different from matrix 2. I >> > consider using a chi-squared test. Is this appropriate? >> > Could anyone advise? >> > Many thank you. >> > Aaral Singh >> > >> > -- >> > View this message in context: >> http://r.789695.n4.nabble.com/help-please-2-tables-which-test-tp4456312p4456312.html >> > Sent from the R help mailing list archive at Nabble.com. >> > >> > ______________________________________________ >> > [email protected] 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. >> >> >> >> -- >> Gregory (Greg) L. Snow Ph.D. >> [email protected] >> >> ______________________________________________ >> [email protected] 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. >> > > [[alternative HTML version deleted]] > > ______________________________________________ > [email protected] 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. ______________________________________________ [email protected] 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.
