search for: depcptwithextybf

Hi, I am trying to add multiple variance structures such as the first example below: vf1 <- varComb(varIdent(form = ~1|Sex), varPower()) However my code below will not work can anybody please advise me? VFcomb<-varComb(varExp(form=~depcptwithextybf),varFixed(form=~FebNAO)) also if you have two variables with the same weights function would you write that as: VFcomb<-varComb(varExp(form=~depcptwithextybf),varExp(form=~FebNAO)) thanks Rebecca -- View this message in context: http://www.nabble.com/Dealing-with-heterogeneity-with-varComb...