On Mon, 4 Dec 2006, Marc Bernard wrote: > Dear All, > > I am trying to use stepAIC for an lmer object but it doesn't work. Here is > an example:
No, and it is not documented to work with lmer objects. stepAIC is support software for a book, and lmer is not discussed in that book (and postdates the book considerably). lmer does not return an object of the type considered by stepAIC (it has an S4 class and it not at all similar to e.g. glm). > > x1 <- gl(4,100) > x2 <- gl(2,200) > time <- rep(1:4,100) > ID <- rep(1:100, each=4) > Y <- runif(400) <=.5 > levels(Y) <- c(1,0) > dfr <- as.data.frame(cbind(ID,Y,time,x1,x2)) > > > fm0.lmer <- lmer(Y ~ time+x1+x2 + (1|ID), data = dfr, family = binomial) > > fm.lmer <- stepAIC(fm0.lmer,scope = list(upper = ~I(time-6)*SF_0_N4*SEX, > lower = ~1,trace = FALSE)) > > I obtain the following error: > > Error in terms.default(object) : no terms component > > I would be very grateful for any suggestion, > > Bernard, > > > > > > > --------------------------------- > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@stat.math.ethz.ch 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. > -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ R-help@stat.math.ethz.ch 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.
