Hi Bill,

Thanks for your reply. I do work with SAS people, so I may have picked up
some of their jargon. I've also heard least square means referred to as
marginal means. I understand them to be group means after having controlled
for a covariate (i.e. holding it constant at some typical value of the
covariate, such as its mean value).

As an example, if my model is specified as:

model<-glm(count~value+group,quasipoisson)

where count is to be explained by value and group (which are continuous and
categorical predictors, respectively) I would like to calculate mean counts
for each group while controlling for value (i.e., holding it constant).

Thank you.
--
Mark Tuscan
Ph.D. Candidate
Cornell University



> From: <Bill.Venables@csiro.au>
> Date: Tue, Aug 5, 2008 at 9:41 PM
> Subject: RE: [R] How to calculate GLM least square means?
> To: mtb954@gmail.com, r-help@r-project.org
>
>
> Can you explain what is a "least square mean"?  It sounds like SAS talk to
> me.
>
> Also, care to tell us who you really are?
>
>
> Bill Venables
> http://www.cmis.csiro.au/bill.venables/
>
> "A propaganda é a alma do negocio"
>
>
> -----Original Message-----
> From: r-help-bounces@r-project.org [mailto:r-help-bounces@r-project.org]
> On Behalf Of mtb954
> Sent: Wednesday, 6 August 2008 1:09 PM
> To: r-help@r-project.org
> Subject: [R] How to calculate GLM least square means?
>
> Hello R-helpers,
>
> I would like to calculate least square means after having built a GLM with
> quasipoisson errors.
>
> In my model the dependent variable is continuous, I have one continuous
> independent variable and one categorical independent variable (that is the
> variable for which I would like to calculate the least square means).
>
> I've looked around for the command to calculate the least square means, but
> I can't find it.
>
> Thanks for your help, Mark
>
>         [[alternative HTML version deleted]]
>
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>
>
>

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