I am using lme from the nlme package to fit a mixed model.  We have observations nested in patients(encounters) and patients nested in groups (2 different treatments).  We are interested in the differences between the 2 groups, both the means and the standard deviations (are patients in group A less variable than those in group B? both within patient and between patient within group).
 
Here is the call from my lme object:
 
> fit3$call
lme.formula(fixed = BG ~ group, data = bg, random = list(Encounter = pdDiag(~group - 
    1)), weights = varIdent(form = ~1 | group))

then I call the intervals function:
 
Approximate 95% confidence intervals
 Fixed effects:
                lower      est.     upper
(Intercept) 123.40005 126.88445 130.36885
groupB       17.44991  23.60049  29.75107
attr(,"label")
[1] "Fixed effects:"
 Random Effects:
  Level: Encounter 
              lower     est.    upper
sd(groupA) 16.62769 19.13351 22.01698
sd(groupB) 24.01774 27.63703 31.80171
 Variance function:
      lower      est.     upper
A 0.8270135 0.8534733 0.8807797
attr(,"label")
[1] "Variance function:"
 Within-group standard error:
   lower     est.    upper 
33.56082 34.29237 35.03987 

and this gives me most of what I want, the only exception is that I (actully my client) want the interval for the Within-group standard error of group A (the last interval shows it for group B and the Variance function shows the interval for their ratio).
 
Any suggestions?
 
Thanks,

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