[R-sig-ME] Contrasts with nlme
jropers at gmail.com
Tue Nov 10 21:11:41 CET 2009
I'm modelling some longitudinal data (1 continuous
response variable measured at 6 times (covariate time taken as factor),
1 continuous baseline, one "treatment" variable also taken as a factor)
collected in the same subjects using the following model:
model.lme<- lme(response ~ V0+ time + tt + tt:time, random =
~1|subject,correlation = corSymm(form = ~ 1 | subject),
Then I would lke to estimate the effect of "treatment" at time = 6 using
the package "contrast"
a = list(tt="1",time="6"),
b = list(tt="0",time="6")
But I get the following error message
"Erreur dans gendata.default(fit = list(modelStruct = list(reStruct =
list(: not enough factors"
I'm obviously doing something wrong.
Thanks for your help.
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