Why compute the differences manually when `aov` can do paired comparisons on this data as is:
summary(aov(extra ~ factor(group) + Error(ID), data=sleep )) gives the same F and P values On Tue, Dec 27, 2022 at 3:32 AM Gabor Grothendieck <ggrothendi...@gmail.com> wrote: > > Good idea. > > On Mon, Dec 26, 2022 at 12:59 PM peter dalgaard <pda...@gmail.com> wrote: > > > > My usual advice on getting nonstandard F tests out of anova() is to fit the > > models explicitly and compare. > > > > So how about this? > > > > fit1 <- lm(diff(extra,10) ~ 1, sleep) > > fit0 <- update(fit1, ~ -1) > > anova(fit0, fit1) > > > > -pd > > > > > On 26 Dec 2022, at 13:49 , Gabor Grothendieck <ggrothendi...@gmail.com> > > > wrote: > > > > > > Suppose we want to perform a paired test using the sleep data frame > > > with anova in R. Then this works and gives the same p value as > > > t.test(extra ~ group, sleep, paired = TRUE, var.equal = TRUE) > > > > > > ones <- rep(1, 10) > > > anova(lm(diff(extra, 10) ~ ones + 0, sleep) > > > > > > This gives output but does not give an F test at all. > > > > > > ones <- rep(1, 10) > > > anova(lm(diff(extra, 10) ~ 1, sleep) > > > > > > Maybe there should be some way to force an F test to be produced for > > > the intercept in anova for consistency with t.test so that the second > > > code can be used. > > > > > > > > > -- > > > Statistics & Software Consulting > > > GKX Group, GKX Associates Inc. > > > tel: 1-877-GKX-GROUP > > > email: ggrothendieck at gmail.com > > > > > > ______________________________________________ > > > R-devel@r-project.org mailing list > > > https://stat.ethz.ch/mailman/listinfo/r-devel > > > > -- > > Peter Dalgaard, Professor, > > Center for Statistics, Copenhagen Business School > > Solbjerg Plads 3, 2000 Frederiksberg, Denmark > > Phone: (+45)38153501 > > Office: A 4.23 > > Email: pd....@cbs.dk Priv: pda...@gmail.com > > > > > -- > Statistics & Software Consulting > GKX Group, GKX Associates Inc. > tel: 1-877-GKX-GROUP > email: ggrothendieck at gmail.com > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel -- Gregory (Greg) L. Snow Ph.D. 538...@gmail.com ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel