[R] augPred plot in nlme library

Afshartous, David afshart at exchange.sba.miami.edu
Fri Sep 8 23:18:13 CEST 2006


Thanks for your suggestion.  Here are more details:

I have a grouped data object for repeated measures data just like the
Pixel grouped data object on p.42 of Pinheiro and Bates (2000).

comp.adj.UKV.3 <- groupedData(adj.UKV ~ Time | Patient_no/Lisinopril, 
	data = comp.adj.UKV.frm, order.groups = F
	#labels = list(x = "Hour", y = "adj.UKV") 

i.e., the response is continuous, Time is not treated as a factor, and
there exists two factors, one nested within the other (Lisinopril nested

witin patient, similar to Side within Dog on p.42).

I also fit a model very similar to their model:

fm1comp = lme(adj.UKV ~ Time + Time.sq, data = comp.adj.UKV.3, random =
list(Patient_no = ~ 1 , Lisinopril = ~ 1) )

However, the command below does not produce the fitted curves from this
but rather it seems to be the fitted curves from a linear model.


Possibly augPred behaves differently in R than in S, but reading the R
help and 
trying various other approaches has not solved this.


-----Original Message-----
From: Deepayan Sarkar [mailto:deepayan.sarkar at gmail.com] 
Sent: Friday, September 08, 2006 4:37 PM
To: Afshartous, David
Cc: r-help at stat.math.ethz.ch
Subject: Re: [R] augPred plot in nlme library

On 9/8/06, Afshartous, David <afshart at exchange.sba.miami.edu> wrote:
> All,
> I've solved part of the problem below by making sure that the formula 
> in the grouped data object is the same as the formula specified within

> lme (this isn't the case in the cited example from Pinheiro & Bates).
> However, augPred seems to plot only a linear model instead of the 
> polynomial model.  Does anyone know how to make sure that augPred 
> plots the same model as that specified in the model (as below)?

You are unlikely to get any helpful answers unless you give us more
information, as every r-help message asks you to do:

> R-help at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.


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