Dear all, I have a problem with interactions in lmer. I have 2 factors (garden and gebiet) which interact, plus one other variable (home), dataframe arr. When I put: / lmer (biomass ~ home + garden:gebiet + ( 1|Block), data = arr)/
it writes: /Error in lme4::lFormula(formula = biomass ~ home + garden:gebiet + (1 | : rank of X = 28 < ncol(X) = 30/ In the lmer help I found out that if not all combination of the interaction are realized, lmer has problems and one should do new variable using "interaction", which I did: / arr$agg <- interaction (arr$gebiet, arr$garden, drop = TRUE)/ when I fit the interaction term now: / lmer (biomass ~ home + agg+ ( 1|Block), data = arr)/ The error does not change: / Error in lme4::lFormula(formula = biomass ~ home + agg + (1 | Block), : rank of X = 28 < ncol(X) = 29/ No NAs are in the given variables in the dataset. Interestingly it works when I put only given interaction like /lmer (biomass ~ agg + ( 1|Block), data = arr)/ Even following models work: /lmer (biomass ~ gebiet*garden + ( 1|Block), data = arr) lmer (biomass ~ garden + garden:gebiet +( 1|Block), data = arr)/ But if I add the interaction term in th enew formate of the new fariable, it reports again the same error. /lmer (biomass ~ garden + agg +( 1|Block), data = arr)/ If I put any other variable from the very same dataframe (not only variable "home"), the error is reported again. I do not understand it, the new variable is just another factor now, or? And it is in the same dataframe, it has the same length. Does anyone have any idea? Thanks a lot, Anna -- View this message in context: http://r.789695.n4.nabble.com/problem-with-interaction-in-lmer-even-after-creating-an-interaction-variable-tp4679951.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.
