Kevin Wright <kw.stat <at> gmail.com> writes: > > > I am trying to teach myself R and replicate some previous SAS analysis. > > Could someone please help me translate the following SAS code into R. > > > > Proc mixed method=ml > > Class Group Treatment Stream Time Year; > > Model Logrpk=Treatment Time Treatment*Time; > > Random Group Stream (Group Treatment) Year(Time); > > > > Assuming you have a data frame "dat" with these factors: Group Treatment > Stream Time Year > And continuous response: logrpk > > This code is a starting point: (I'm not sure exactly what the SAS syntax > means). > > require(lme4) > m1 = lmer(logrpk ~ treatment*time + (1|Group) + (1|Stream:Group:Treatment) + > (1|Year:Time), data=dat) >
Can I please suggest that (Treatment|Stream:Group) or something like it is more appropriate than (1|Stream:Group:Treatment)? In general, what goes on the LEFT of the bar is an intercept or fixed effect (i.e. something that varies between groups); what goes on the RIGHT of the bar is a grouping variable. Thus if a fixed effect terms ends up on the right of the bar, something funny is going on. Ben Bolker ______________________________________________ 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.
