I'm having another problem with lmer(), this time something simpler (I think) involving the coef() function for a model with varying coefficients. Here's the R code. It's a simple model with 2 observations per group and 10 groups:
# set up the predictors n.groups <- 10 n.reps <- 2 n <- n.groups*n.reps group.id <- rep (1:n.groups, each=n.reps) # simulate the varying parameters a.group <- rnorm (n.groups, 1, 2) # simulate the data and print to check that i did it right y <- rnorm (n, a.group[group.id], 1) print (cbind (y, group.id)) # fit and summarize the model fit.1 <- lmer (y ~ 1 + (1 | group.id)) summary (fit.1) # coef() doesn't work! coef (fit.1) -- The following error message came: Error in "rownames<-"(x, value) : attempt to set rownames on object with no dimensions -- So I went into the code and the coefficient info is there. There just seems to be some "bookkeeping problem" within coef(). I could kludge something but I'd rather work within the existing structures and use coef() which seems intended for this purpose. OK, then I tried adding a predictor and it worked fine: x <- rnorm (n) fit.2 <- lmer (y ~ 1 + x + (1 | group.id)) summary (fit.2) coef (fit.2) -- Am I doing something stupid here or is it actually a (minor) bug? Thanks Andrew -- Andrew Gelman Professor, Department of Statistics Professor, Department of Political Science [EMAIL PROTECTED] www.stat.columbia.edu/~gelman Tues, Wed, Thurs: Social Work Bldg (Amsterdam Ave at 122 St), Room 1016 212-851-2142 Mon, Fri: International Affairs Bldg (Amsterdam Ave at 118 St), Room 711 212-854-7075 Mailing address: 1255 Amsterdam Ave, Room 1016 Columbia University New York, NY 10027-5904 212-851-2142 (fax) 212-851-2164 ______________________________________________ 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
