R help - Sep 2005 - Can I use "lme" to deal with grouping data when I only get one data point per group?

Hi there,
I have a question for using "lme". Say, I have 6 data points and they
belong
to six groups (one group factor). So there is no replicates for each group 
and I cannot separate the with-in group variation from the between group 
variation. 
But when I try to use "lme" to deal with it, it gave the answers for
both
with-in group variation and the between group variation! The statement is as 
below:
==============================================================
fac=as.factor(c(1:6))

y=data

data.y=data.frame(y,fac)

y.g=groupedData(y~1|fac)

fit.y=lme(y~1,random=~1|fac)
============================================An example is:
y=c(-0.3465181, -0.2019839, -0.7610653, -0.1992943, -0.1663348, 0.2811794)
then the lme gave me the variance components:
0.09865809 (intercept , between-group variance)
0.01387379 (residual, with-in group variance)
 So, my question is, from theory we cannot get separate estimates of with-in 
group variation and the between group variation, then what dose the output 
of the "lme" mean?


Thanks!
 Ruixiao

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Ruixiao Lu <tinypenguin <at> gmail.com> writes:
> I have a question for using "lme". Say, I have 6 data points and
they belong
> to six groups (one group factor). So there is no replicates for each group 
> and I cannot separate the with-in group variation from the between group 
> variation. 
> But when I try to use "lme" to deal with it, it gave the answers
for both
> with-in group variation and the between group variation! The statement is
as
> below:
((Slightly modified by DM))

fac=as.factor(c(1:6))
y=c(-0.3465181, -0.2019839, -0.7610653, -0.1992943, -0.1663348, 0.2811794)
data.y=data.frame(y,fac)
y.g=groupedData(y~1|fac)
intervals(y.g) ## and you will see ....

Similar example on page 27 of Pinheiro/Bates

Dieter Menne