Hi, I'm having some problems regarding the packages lme4 and nlme, more specifically in the denominator degrees of freedom. I used data Orthodont for the two packages. The commands used are below.
require(nlme) data(Orthodont) fm1<-lme(distance~age+ Sex, data=Orthodont,random=~1|Subject, method="REML") anova(fm1) numDF DenDF F-value p-value (Intercept) 1 80 4123.156 <.0001 age 1 80 114.838 <.0001 Sex 1 25 9.292 0.0054 The DenDF for each fixed effect is 80, 80 and 25. Using the package lme4: require(lme4) data(Orthodont) fm2<-lme(distance~age+ Sex, data=Orthodont,random=~1|Subject, method="REML") anova(fm2) numDF Sum Sq Mean Sq DenDF F-value p-value age 1 235.356 235.356 105 114.838 <2.2e-16 Sex 1 19.044 19.044 105 9.292 0.002912 In this case the DenDF for each fixed effect is 105 and 105. In this example, the conclusions are still the same, but it's not the case with another dataset I analyzed. I experience the same type of problem when using glmmPQL of the MASS package and the GLMM of package lme4. Could anyone give me a hint on why the two functions are giving incompatible results? thank you in advance for your help Alexandre Galvão Patriota. _______________________________________________________ Yahoo! Acesso Grátis - navegue de graça com conexão de qualidade! ______________________________________________ [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