R help - Feb 2006 - Extracting variance components from lmer

Hi All.

I need a bit of help extracting the residual error variance from the VarCorr
structure from lmer.

#Here's a 2-way random effects model
lmer.1    <- lmer(rating ~ (1|person)+(1|rater), data = dat)

#Get the structure
vc.fit <- VarCorr(lmer.1)

#results in.....
$person
1 x 1 Matrix of class "dpoMatrix"
            (Intercept)
(Intercept)   0.7755392

$rater
1 x 1 Matrix of class "dpoMatrix"
            (Intercept)
(Intercept)   0.2054469

attr(,"sc")
[1] 0.5051518

#I can pull out the person and rater variance components easy enough. For
example...
vc.person <- vc.fit$person@x

I'm sure it's simple but I have not been able to grab the residual
variance
in the last matrix.  I simply wish to asign the residual to a scalar
variable.  Any suggestions would be appreciated!

Thanks!

Rick DeShon


--
Rick DeShon
306 Psychology Building
Department of Psychology
Michigan State University
East Lansing, MI 48824-1116

	[[alternative HTML version deleted]]

Hi Rick 

There may be a better way, but the following should work: 
 
attributes(vc.fit)$sc

Regards,

Christoph Buser

--------------------------------------------------------------
Christoph Buser <buser at stat.math.ethz.ch>
Seminar fuer Statistik, LEO C13
ETH (Federal Inst. Technology)	8092 Zurich	 SWITZERLAND
phone: x-41-44-632-4673		fax: 632-1228
http://stat.ethz.ch/~buser/
--------------------------------------------------------------


Rick DeShon writes:
 > Hi All.
 > 
 > I need a bit of help extracting the residual error variance from the
VarCorr
 > structure from lmer.
 > 
 > #Here's a 2-way random effects model
 > lmer.1    <- lmer(rating ~ (1|person)+(1|rater), data = dat)
 > 
 > #Get the structure
 > vc.fit <- VarCorr(lmer.1)
 > 
 > #results in.....
 > $person
 > 1 x 1 Matrix of class "dpoMatrix"
 >             (Intercept)
 > (Intercept)   0.7755392
 > 
 > $rater
 > 1 x 1 Matrix of class "dpoMatrix"
 >             (Intercept)
 > (Intercept)   0.2054469
 > 
 > attr(,"sc")
 > [1] 0.5051518
 > 
 > #I can pull out the person and rater variance components easy enough. For
 > example...
 > vc.person <- vc.fit$person at x
 > 
 > I'm sure it's simple but I have not been able to grab the residual
variance
 > in the last matrix.  I simply wish to asign the residual to a scalar
 > variable.  Any suggestions would be appreciated!
 > 
 > Thanks!
 > 
 > Rick DeShon
 > 
 > 
 > --
 > Rick DeShon
 > 306 Psychology Building
 > Department of Psychology
 > Michigan State University
 > East Lansing, MI 48824-1116
 > 
 > 	[[alternative HTML version deleted]]
 > 
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