"Li, Qishan" <qishan@email.arizona.edu> writes:
> I should be grateful for suggestions on how to do the following:
>
> I am using Splus (nlme) and I want to extract a parameter and use it later.
> The parameter value is 4.077946, which is the StdDev of Asym.
> > My_buffer<- StdDev of Asym , the value is 4.077946
>
> I do not know which function I should use. I tried
> >random.effects(fm2)
> but, it does not work.
>
> Many thanks.
>
> Qishan Li
> ---------------------------------------------
> >fm2 <- nlme(weight ~ SSlogis(Time, Asym, xmid, scal), data = Soybean,
> fixed = Asym + xmid + scal ~ 1, random = pdDiag(Asym + xmid
> ~ 1),
> start = c(18, 52, 7.5))
>
> > fm2
> Nonlinear mixed-effects model fit by maximum likelihood
> Model: weight ~ SSlogis(Time, Asym, xmid, scal)
> Data: Soybean
> Log-likelihood: -755.7323
> Fixed: Asym + xmid + scal ~ 1
> Asym xmid scal
> 18.96426 55.14188 8.55292
>
> Random effects:
> Formula: list(Asym ~ 1, xmid ~ 1)
> Level: Plot
> Structure: Diagonal
> Asym xmid Residual
> StdDev: 4.077946 2.52487 1.1924
>
> Number of Observations: 412
> Number of Groups: 48
as.numeric(VarCorr(fm2)["Asym", "StdDev"])
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