Which mgcv version are you using, and which package (and version number) are you using for the `contrast' function? (I assume you mean `gamm' below, btw)
On Thursday 22 July 2010 20:13, Xia Li wrote: > Dear All, > I met problems when doing contrast and now really need some help in the > model below: > > Fit=gam(y~treat+SEQUENCE+PERIOD+SEX+s(x),data=dat, > random=list(SUBJID=~1),correlation=corAR1(form=~1|SUBJID)) > > And error message keeps coming out when I want to compare the differences > between treatments: > > Diff=contrast(Fit, > list(treat=treatment[-placebo.pos]),list(treat="Placebo"), > conf.int=0.9)-- (here > placebo.pos=position of "Placebo" in treatment vector) > > I wonder if the function contrast could be used here? If not, what other > options I might have? > > I hope it's not a stupid question� > > Thanks a lot! > > Xia Li > > [[alternative HTML version deleted]] -- > Simon Wood, Mathematical Sciences, University of Bath, Bath, BA2 7AY UK > +44 1225 386603 www.maths.bath.ac.uk/~sw283
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