The short answer is that lm() is written more robustly. I don't think either should fail, but without a reproducible example it is hard to tell.
On Mon, 2 Apr 2007, Michael Kubovy wrote: > Dear r-helpers, > > Can anyone suggest why lm() doesn't complain here: > > summary(osss.lm1 <- lm(logOdds ~ c.setSize %in% task, data = osss)) > > whereas in package:nlme (and in package:lme4) > > osss.lmL <- lmList(logOdds ~ c.setSize %in% task | subj, data = osss) > # Error in `contrasts<-`(`*tmp*`, value = "contr.treatment") : > # contrasts can be applied only to factors with 2 or more levels > > If it were because for each subj I have only 1 datum per cell: > > with(subset(osss, osss$subj == '42'), table(setSize, task)) > # task > # setSize os ss > # 2 1 1 > # 3 1 1 > # 4 1 1 > # 5 1 1 > # 6 1 0 > # 7 1 0 > > then > > osss.lm1 <- lm(logOdds ~ c.setSize %in% task, data = subset(osss, osss > $subj == '42')) I don't know what c.setSize is, but data=osss, subset=subs=='42' is a much clear way to write this lm() call. > should fail as well, but I get > > anova(osss.lm1) > # Analysis of Variance Table > # > # Response: logOdds > # Df Sum Sq Mean Sq F value Pr(>F) > # c.setSize:task 2 6.8269 3.4134 1.9976 0.2059 > # Residuals 7 11.9612 1.7087 > > > _____________________________ > Professor Michael Kubovy > University of Virginia > Department of Psychology > USPS: P.O.Box 400400 Charlottesville, VA 22904-4400 > Parcels: Room 102 Gilmer Hall > McCormick Road Charlottesville, VA 22903 > Office: B011 +1-434-982-4729 > Lab: B019 +1-434-982-4751 > Fax: +1-434-982-4766 > WWW: http://www.people.virginia.edu/~mk9y/ > > ______________________________________________ > [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 > 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 ______________________________________________ [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 and provide commented, minimal, self-contained, reproducible code.
