Julie BERTRAND <[EMAIL PROTECTED]> writes: > hello, > > after an anova I use pairwise.t.test(), it gives only > p.value and I want the t.stat. > I try to get these by computing the Welch > approximation of the degree of freedom and using the > qt(p.value,df) function but when I test this method > with t.test results (the function gives p.value and > t.test), I doesn't find the same t.stat. > > I also use the simtest(x~y,type="Tukey") function and > it gives me only negative t.stat, resulting in a weard > distribution... > > thank you in advance for all the attention you 'll > give to my problems. > Julie BERTRAND
Notice that the p-values in pairwise.t.test() are adjusted for multiple comparisons and use a pooled SD. You're not going to get anything similar to the t.test output unless you set pool.sd=FALSE and p.adjust.method="none". You probably also want to make the tests one-sided, or halve the p-value. It could well be easier just to modify the function to give you the result that you desire... -- O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 ______________________________________________ [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
