Sorry to come back again, but with this and other (real) data, I'm not able to obtain those comparisons. I'm using the following command and obtain the following result (lmer model).
glht(lmelac.ex, linfct = mcp("ath1:tim20 - ath1:tim40 = 0"="Tukey"))->comp Erreur dans mcp2matrix(model, linfct = linfct) : Variable(s) ‘ath1:tim20 - ath1:tim40 = 0’ have been specified in ‘linfct’ but cannot be found in ‘model’! After looking at the model obtained in nlme, the interactions are not present. However, I'm not able to find any object in lmer objects May I ask for your help again? THanks a lot Virgile Dieter Menne wrote: > > > > Billeke wrote: >> >> >> mult2 <- glht(lmelac.ex, linfct = mcp("ath:time" = "Tukey")) >> >> > > I don't have the time to check, but got a mail for Torsten (author) with > the following idea: > > glht(lmeglu, linfct = c("Ath1:tim2 - Ath1:tim3 = 0", ...)) > > He suggested to build the matrix explicitly instead; that's what I > normally do, but I admit that I use an Excel spreadsheet to get the > coefficients right in such a case. > > Technically, using time as a categorical parameter is not recommended > because of serial correlations. Try to fit a linear or linearized model > instead to time, or, if you cannot do it otherwise, a nonlinear one. > > I too often see my colleagues asking questions like "how many days after > treatment start do I first see significant effects on my lymphocyte > count"? This gives many p-values for a publication, and that's what > medical reviewers love. Your approach to use multcomp to correct for this > is a fair way out, but doing serious trend analysis is better. > > Dieter > > > > > > > > > > -- View this message in context: http://www.nabble.com/Multiple-comparison-on-lme-model-with-2-fixed-factors-tp25002051p25023041.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.