My question relates to problems that I'm having matching lme and lmer
examples in P&B. 
using Matix 0.995
 
In the Oxide example in p167-170 I can't get the level 2 coefficient
estimates to match 
the fm1Oxide model in lme is 
 
data(Oxide,package="nlme")
lme(Thickness~1,Oxide)

which I translate in Lmer syntax to 
 
fm3Oxide<-lmer(Thickness~ (1|Lot)+(1|Lot:Wafer),data=Oxide)
#or alternatively which gives the same result
Oxide$LW<-with(Oxide,Lot:Wafer)[drop=TRUE]
fm4Oxide<-lmer(Thickness~ (1|Lot)+(1|LW),data=Oxide)
 
however if you look at say Lot 8, lme gives
 
8    1993.767

8/1    1993.677
8/2    1995.170
8/3    1990.693

 
while  lmer gives 
coef(fm3Oxide)
....
8    1993.767
8:1 2000.062

8:2 2001.555

8:3 1997.078

To me this looks like lmer in not including the lot random effect (8=
-6.385129, Intercept 2000.153 ). Is this because I'm not specifying the
model correctly?

Thanks Paul

 


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