[R-sig-ME] Contrast in lme4

[Viechtbauer Wolfgang (STAT)]

I think these may be helpful to the OP:

http://www.ats.ucla.edu/stat/r/library/contrast_coding.htm

http://www.ats.ucla.edu/stat/r/faq/testing_contrasts.htm

Best,
Wolfgang

> -----Original Message-----
> From: R-sig-mixed-models [mailto:r-sig-mixed-models-bounces at r-
> project.org] On Behalf Of Ben Bolker
> Sent: Thursday, March 12, 2015 19:55
> To: r-sig-mixed-models at r-project.org
> Subject: Re: [R-sig-ME] Contrast in lme4
> 
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> 
>   "How do I set up custom contrasts?" is (1) not specific to mixed
> models (so not really appropriate for this list -- maybe try r-help or
> Stack Overflow); (2) rather tricky in R (it may be difficult in all
> statistics packages/languages, I don't know); and (3) sufficiently
> detailed that the information you give below isn't really quite
> sufficient.  A reproducible example will help when you post your
> question somewhere else.  You can use the "contrast" package, or the
> "multicomp" package, to test contrasts.  As far as how the contrasts
> are set up, there's a reasonable description in Crawley's _Data
> Analysis in S-PLUS_ book, or see
> 
> http://www.ats.ucla.edu/stat/r/library/contrast_coding.htm
> http://ms.mcmaster.ca/~bolker/classes/s4c03/notes/week2B.pdf
> 
> 
> On 15-03-12 01:52 PM, Douglas Bates wrote:
> > It is better to send questions like this to the
> > R-SIG-Mixed-Models at R-project.org mailing list, which I am cc:ing on
> > this reply.
> >
> > On Thu, Mar 12, 2015 at 3:09 AM adeela uaf <adeela.uaf at gmail.com>
> > wrote:
> >
> >> Dear Douglas Bates, How to perform contrast analysis for fixed
> >> effects in lme4 package. My data is same as sleepstudy data with
> >> an additional cloumn comprising  12 treatments also. The
> >> structure of the treatmnets is such that: 1) 1 treatment is
> >> control 2) 4 treatments are bio-agents. 3) 3 treatments are
> >> botanical. 4) 2 are bi prodcts 5) 2 are fungisides I want to make
> >> comparison among the groups which differ significantly after
> >> Model<-lmer(Disease~Trt+Date+Trt*Date+(1|Subject),data=YR) Best
> >> Regars, Adeela
> >>
> >
> > [[alternative HTML version deleted]]
> >
> > _______________________________________________
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> >
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