Displaying 14 results from an estimated 14 matches similar to: "formula, how to express for transforming the whole model.matrix, data=Orthodont"
2010 Oct 18
1
Question about lme (mixed effects regression)
Hello!
If I run this example:
library(nlme)
fm1 <- lme(distance ~ age+Sex, Orthodont, random = ~ age + Sex| Subject)
If I run:
summary(fm1)
then I can see the fixed effects for age and sex (17.7 for intercept,
0.66 for age, and -1.66 for SexFemale)
If I run:
ranef(fm1)
Then it looks like it's producing the random effects for each subgroup
(in this example - each subject). For example,
2002 Jan 12
1
Question about mixed-effects models example (Pinheiro and Bates)
Hi all,
I'm trying to figure out the example about mixed models in the Pinheiro
and Bates book (Mixed-Effects Models in S and S-Plus, 2000, pp. 135-137).
One thing I don't understand is:
When I run the command
fm1Orth.lm <- lm( distance ~ age, Orthodont )
followed by
fm2Orth.lm <- update( fm1Orth.lm, formula = distance ~ Sex*age )
and then do
summary(fm2Orth.lm)
2010 Jun 22
2
xyplot: adding pooled regression lines to a paneled type="r" plot
Consider the following plot that shows separate regression lines ~ age
for each subject in the Pothoff-Roy Orthodont data,
with separate panels by Sex:
library(nlme)
#plot(Orthodont)
xyplot(distance ~ age|Sex, data=Orthodont, type='r', groups=Subject,
col=gray(.50),
main="Individual linear regressions ~ age")
I'd like to also show in each panel the pooled OLS
2010 May 19
8
Generating all possible models from full model
Is there a function that will allow me to run all model iterations if I specify a full model? I am using information criteria to choose between possible candidate models. I have been writing out all possible model combinations by hand, and I am always worried that I am missing models or have made a mistake somewhere. It is also difficult to alter models if I want to change a term. For example,
2011 Jul 04
1
Contrastes con el paquete survey (svycontrast)
Estimados usuarios:
Estoy intentando reproducir el ejemplo 6.4 de Thomas Lumley. Complex
Survey. Editorial Wiley. 2010 (ver la página en google:
2008 Dec 12
1
How can we predict differences in a slope, given that the random component was significant?
Dear R users,
Using R lme function, I found that both fixed and random effects of variable
A on variable B are significant. Now, I'd like to analyze what variables
are predicting differences in the slope. In other words, I'd like to know
what variables (e.g., variable C) are predicting individual differences in
the effects of A on B. I have many data points for A and B for each
2005 Nov 25
0
multiple imputation of anova tables
Dear list members,
how can multiple imputation realized for anova tables in R? Concretely,
how to combine
F-values and R^2, R^2_adjusted from multiple imputations in R?
Of course, the point estimates can be averaged, but how to get
standarderrors for F-values/R^2 etc. in R?
For linear models, lm.mids() works well, but according to Rubins rules,
standard errors have to be used together with
2011 Sep 29
0
geeglm estimates and standard deviation are too large
Hi,
I'm using geeglm function to account for the repeated measure.
fit1<- geeglm( binary.outcome ~ age + race + gender + fever.yes.no,
data=mydata, id=ID, family=binomial, corstr="exchangeable")
summary(fit1)$coef gives too large estimates and standard deviation:
Estimate Std.err Wald Pr(>|W|)
(Intercept) 3.07e+16
2004 Oct 16
3
Cox PH Warning Message
Hi,
Can anybody tell me what the message below means and how to overcome it.
Thanks,
Neil
Warning message:
X matrix deemed to be singular; variable 2 in: coxph(Surv(age_at_death,
death) ~ project$pluralgp + project$yrborn + .........
>
2013 Jan 11
0
Experimental Opus support in Chrome
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
In addition to Chrome's support for Opus in WebRTC, Tom Flanagan has
added support for .opus files in the HTML <audio> element, similar to
what Firefox has. It's currently behind a switch, so you'll need to
pass --enable-opus-playback to M25 or M26 to evaluate.
I tried some the files https://people.xiph.org/~greg/opus_testvectors/
2008 Aug 28
1
Adjusting for initial status (intercept) in lme growth models
Hi everyone, I have a quick and probably easy question about lme for this
list.
Say, for instance you want to model growth in pituitary distance as a
function of age in the Orthodont dataset.
fm1 = lme(distance ~ I(age-8), random = ~ 1 + I(age-8) | Subject, data =
Orthodont)
You notice that there is substantial variability in the intercepts (initial
distance) for people at 8 years, and that
2009 Apr 26
2
7.2-PRE amd64 panic when starting Xorg
Hi,
I've installed 7.2-PRERELEASE, csup on 20090423 at around 19:00 UTC.
When I rebooted after installing world, X started (xdm in /etc/ttys)
and immediately panicked the system, even before switching to the new
VTY. I removed all ports and installed Xorg from today's ports HEAD,
same result. This is the case with my old xorg.conf and a new one
from 'Xorg -configure'.
I
2011 Mar 31
2
ANCOVA for linear regressions without intercept
Hello R experts
I have two linear regressions for sexes (Male, Female, Unknown). All have a good correlation between body length (response variable) and head length (explanatory variable). I know it is not recommended, but for a good practical reason (the purpose of study is to find a single conversion factor from head length to body length), the regressions need to go through the origin (0
2008 Jun 30
4
Rebuild of kernel 2.6.9-67.0.20.EL failure
Hello list.
I'm trying to rebuild the 2.6.9.67.0.20.EL kernel, but it fails even without
modifications.
How did I try it?
Created a (non-root) build environment (not a mock )
Installed the kernel.scr.rpm and did a
rpmbuild -ba --target=`uname -m` kernel-2.6.spec 2> prep-err.log | tee
prep-out.log
The build failed at the end:
Processing files: kernel-xenU-devel-2.6.9-67.0.20.EL
Checking