[R] Evaluating outer observations in an lme object.

CG Pettersson cg.pettersson at evp.slu.se
Fri Sep 19 19:51:35 CEST 2003

Oh, the question might have been more precisely formulated I guess...

"update" surely helps a lot in the practical work at the computer. But
that is not my problem. The problem is where and how to introduce the
variables in the command.

I´ve tried things like:     random = ~ P.AL | Trial/Block 
as the random call, looking for some sort of direct effect from the
soil analysis P.AL. That results in a worse model than without the
term, possibly becouse the effect of the soil already is,
implicitlely, inside the term Trial.
What I am looking for is a way of evaluating several factors that have
just one observation for each Trial, still having the the nice
Trial/Block structure present in the model. 

Or am I just stupid?


> Might "update" help?  spencer graves
> CG Pettersson wrote:
> >Hello everybody!
> >I´m working with a dataset from twelve fertilizer trials, where the
> >technical fertilizer product and application method, but not the
> >intensity of fertilization, is varied. (I´m using R1.7.1 and
> >
> >The call:
> >
> >ejna1t4b.lme <- lme( Yield ~ TrCode, data = ejna1t4,
> >+                       random = ~ 1 | Trial/Block)
> >
> >works as far as I can understand well, the Block structure of the
> >trials is used efficiently and everything looks nice according to
> >plots of the object.
> >
> >Now I want to evaluate the influence of observations from the
> >different experimental places (for example soil analyses or
> >- Could I do that without skipping the Trial/Block structure, or do
> >have to start from scratch again? The observed values will
> >only have one level for each Trial, so the term Trial/Block will
> >the effects of all observed (and unobserved) phenomena in each
> >Now I want to know where the effects come from.
> >
> >I´ve been looking for a text on this, both in MASS and Pinheiro &
> >Bates, without finding any. Any hints of where to look?
> >
> >Thanks
> >/CG
> >
> >CG Pettersson, MSci, PhD Stud.
> >Swedish University of Agricultural Sciences
> >Dep. of Ecology and Crop Production. Box 7043
> >SE-750 07 Uppsala
> >
> >______________________________________________
> >R-help at stat.math.ethz.ch mailing list
> >https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> >  
> >
CG Pettersson, MSci, PhD Stud.
Swedish University of Agricultural Sciences
Dep. of Ecology and Crop Production. Box 7043
SE-750 07 Uppsala

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