[R] Standard errors of least squares adjusted means

[John Fox]

Dear Bruno,

See the effects package (on CRAN) for a generalization of adjusted means.

I hope this helps,
 John

------------------------------
John Fox, Professor
Department of Sociology
McMaster University
Hamilton, Ontario, Canada
web: socserv.mcmaster.ca/jfox

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On
> Behalf Of Bruno Estigarribia
> Sent: January-22-09 12:32 AM
> To: r-help at r-project.org
> Subject: [R] Standard errors of least squares adjusted means
> 
> Hello,
> 
> I have the following model:
> lm.7 <- lm(Y ~ F + C1 + C2 , data = EM4)
> F is a 4-level factor, the rest are covariates centered at their mean (Y
> is a two-column matrix).
> I have tried to find functions to give the model-adjusted means
> (adjusted at the covariates'means) and their standard deviations for each.
> (That is, what I believe is called in SAS "least square or LS-means,
> whose errors one obtains by STDERR)
> I have tried help.search and RSiteSearch with several terms including
> "standard errors", "least square means", "adjusted means". I have found
> how to extract the SE from coefficients (se.coef from package arm), or
> the SE for contrasts (se.contrast from package stats), but not the SE
> for an adjusted mean.
> Thank you,
> 
> --
> Bruno Estigarribia
> Postdoctoral Fellow
> FPG Child Development Institute
> Neurodevelopmental Disorders Research Center
> University of North Carolina at Chapel Hill
> 
> 105 Smith Level Rd
> Chapel Hill, NC 27599-8180
> USA
> + 1 (919) 843-7685
> 
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