Displaying 20 results from an estimated 4000 matches similar to: "weights in mixed model"
2003 Sep 05
3
fit data with skew t distribution
Hi,
Is there a function in R that I can use to fit the data with skew t
distribution? Speaking in detail, I first used the kernel density estimation
to fit my data, then I drew the skew t using my specified location, scale,
shape, and df to make it close to the kernel density. Now I want to get the
parameter estimations of the skew t which give me the closet density to the
kernel density.
2005 Mar 14
4
The corresponding Fortran77 codes for R function pt()
Hi,
I'm trying to find the corresponding Fortran77 subroutines for R
function pt(). I tried some Fortran77 subroutines to compute the t
distribution function. But none of them are as good as R function pt().
Does anyone can give me some information about it?
Thank you very much!
Tianyue
2003 Dec 05
1
Can anyone help me reproduce this SAS Mixed output??
I asked this before and I am going to try again in more applied terms. I
am trying to use R to extract variance components for a two-factor random
effects model with both factors crossed. It would also be nice to
generate some confidence intervals as well. For example, a data set
using SAS Proc Mixed is below followed by the four variance component
estimates and the respective confidence
2005 Oct 14
1
lattice with predicted values
Dear lattice wizards,
I am trying to figure out how to plot predicted values in xyplot,
where the intercept, but not the slope, varies among conditioning
factor levels. I am sure it involves the groups, but I have been
unsuccessful in my search in Pinhiero and Bate, in the help files, or
in the archive, or in my attempts on my own.
My example follows:
FACT is a factor with levels a,b,c
2009 Jun 23
1
nlme package - unbalanced data and Croissant (2008)
Dear listserv members,
In Croissant (2008) “Panel Data Econometrics in R: The plm Package” the
authors seem to indicate that the nlme package for R cannot correctly handle
unbalanced panel data: “Moreover, economic panel datasets often happen to be
unbalanced (i.e., they have a different number of observations between
groups), which case needs some adaptation to the methods and is not
2008 Aug 25
1
A repeated measures, linear mixed model (lme) WITHOUT random effects...
Hello,
I am trying to fit a repeated measures linear mixed model (using lme)
but I don't want to include any random effects. I'm having trouble (even
after consulting Pinheiro & Bates 2000) figuring out how to specify the
repeated measure without including it in the specification of a random
effect.
My data consist of repeated "counts" in "plots" that I wish
2008 Aug 05
1
Mixed model with multiple response variables?
Hi,
I have a data set collected from 10 measurements (response variables)
on two groups (healthy and patient) of subjects performing 4 different
tasks. In other words there are two fixed factors (group and task),
and 10 response variables. I could analyze the data with aov() or
lme() in package nlme for each response variable separately, but since
most likely there are correlations among the 10
2005 Oct 05
1
Analyses of covariation with lme() or lm()
Hello all!
I have a problem that calls for a better understanding, than mine, of
how lme() uses the random part of the call.
The dataset consists of eleven field trials (Trial) with three
replicates (Block) and four fertiliser treatments (Treat). Analysing for
example yield with lme() is easy:
m1 <- lme(Yield ~ Treat, data=data,
random =~1| Trial/Block)
giving estimates of
2006 May 11
1
Mixed Model notation SAS -> R
Dear experts,
I'm trying to transfer a mixed model developed in SAS to R. This it what
it looks like in SAS:
proc mixed method=ml;
class a b c subj;
model y = a|b|c;
repeated /subject=subj type=ar(1);
I tried something like this in R:
mixed <- lme(y ~ a + b + c + a*b + a*c + b*c + a*b*c,
random = ~ 1 | subj,
correlation = corAR1(form = ~ 1 | subj)
2017 Dec 03
1
Discourage the weights= option of lm with summarized data
Peter,
This is a highly structured text. Just for the discussion, I separate
the building blocks, where (D) and (E) and (F) are new:
BEGIN OF TEXT --------------------
(A)
Non-?NULL? ?weights? can be used to indicate that different
observations have different variances (with the values in ?weights?
being inversely proportional to the variances);
(B)
or equivalently, when the elements of
2003 Oct 04
2
mixed effects with nlme
Dear R users:
I have some difficulties analizing data with mixed effects NLME and the
last version of R. More concretely, I have a repeated measures design with
a single group and 2 experimental factors (say A and B) and my interest is
to compare additive and nonadditive models.
suj rv A B
1 s1 4 a1 b1
2 s1 5 a1 b2
3 s1 7 a1 b3
4 s1 1 a2
2017 Oct 12
4
Discourage the weights= option of lm with summarized data
OK. We have now three suggestions to repair the text:
- remove the text
- add "not" at the beginning of the text
- add at the end of the text a warning; something like:
"Note that in this case the standard estimates of the parameters are
in general not correct, and hence also the t values and the p value.
Also the number of degrees of freedom is not correct. (The parameter
2003 Dec 15
2
help in lme
To anyone who can help,
I have two stupid questions, and one fairly intelligent question
Stupid question (1): is there an R function to calculate a factorial of a number? That is...is there a function g(.) such that g(3) = 6, g(4) = 24, g(6) = 720, etc?
Stupid question (2): how do you extract the estimated covariance matrix of the random effects in an lme object?
Intelligent question
2003 Sep 12
1
nlme and simulation
Dear all,
I would like to simulate data from a nlme model using fixed effects and the
variances of the random effects distribution.
I scanned the help files and the mailing lists with no succes. Thanks for
your help!
Peter
2007 Mar 28
2
error when running ocfs2console (ImportError: No module named ocfs2interface.about)
I had build ocfs2-tools-1.2.3 from sources on x86_64 machine (FC6).
When I run:
ocfs2console
I get:
Traceback (most recent call last):
File "/usr/local/sbin/ocfs2console", line 3, in ?
from ocfs2interface.about import process_args
ImportError: No module named ocfs2interface.about
When I try: locate ocfs2interface.about
I get no result.
Any ideas what went wrong ?
Regards,
Andy
2003 Nov 20
3
Problem with Trellis graphics in nlme
Hi,
I would be grateful for help with a problem which is irritating me.
I am quite sure that I am doing something stupid, but I can't see what it
is.
I am running R 1.7 on Windows 2000. The graphics device is the PC screen.
The graphics from the nlme demonstration in Bates an Pinheiro's manual work
just as advertised. The CO2 data and the Orthodont data dsiplay
2006 Oct 05
2
treatment effect at specific time point within mixedeffects model
Hi David:
In looking at your original post it is a bit difficult to ascertain
exactly what your null hypothesis was. That is, you want to assess
whether there is a treatment effect at time 3, but compared to what. I
think your second post clears this up. You should refer to pages 224-
225 of Pinhiero and Bates for your answer. This shows how to specify
contrasts.
> -----Original Message-----
2017 Jan 20
2
Get Num of Uses in only dominated blocks?
Hi all,
I am doing a project that requires counting the number of uses of a value
only in all dominated blocks in a function. I checked the manual for
llvm::User
class, but only get this
unsigned <http://llvm.org/test-doxygen/api/classunsigned.html> getNumUses
<http://llvm.org/test-doxygen/api/classllvm_1_1Value.html#a380559e99b47632a34f74de7c1d03cc0>
()
const
This gives me all the
2003 Nov 16
1
SE of ANOVA (aov) with repeated measures and a bewtween-subject factor
Hallo!
I have data of the following design:
NSubj were measured at Baseline (visit 1) and at 3
following time points (visit 2, visit 3, visit 4).
There is or is not a treatment.
Most interesting is the question if there is a
difference in treatment between the results of visit 4
and baseline. (The other time points are also of
interest.) The level of significance is alpha=0.0179
(because of an
2006 Feb 08
2
lme syntax for P&B examples
Hi helpeRs,
I've been working through some examples in Pinhiero & Bates( 2000)
trying to understand how to translate to the new Lme4 syntax but without
much luck.
Below is what I think I should do, but either the answers don't come out
the same or I get errors.
In the Oxide problems I'm particularly interested in obtaining the
levels coeficients but this options no longer seems