Displaying 20 results from an estimated 200 matches similar to: "aov for mixed model (fixed and random)?"
2007 Jun 28
2
aov and lme differ with interaction in oats example of MASS?
Dear R-Community!
The example "oats" in MASS (2nd edition, 10.3, p.309) is calculated for aov and lme without interaction term and the results are the same.
But I have problems to reproduce the example aov with interaction in MASS (10.2, p.301) with lme. Here the script:
library(MASS)
library(nlme)
options(contrasts = c("contr.treatment", "contr.poly"))
# aov: Y ~
2003 Jun 17
1
lme() vs aov(y ~ A*B + Error(aa %in% A + bb %in% B)) [repost]
I've posted the following to R-help on May 15.
It has reproducible R code for real data -- and a real
(academic, i.e unpaid) consultion background.
I'd be glad for some insight here, mainly not for myself.
In the mean time, we've learned that it is to be expected for
anova(*, "marginal") to be contrast dependent, but still are
glad for advice if you have experience.
Thank
2010 Sep 16
1
Help for an absolutely r-noob
Hello together,
I am an absolute noob in R and therefore I need help urgently. I have
received a script from my tutor with plot functions in it. However, I can'
manage to adapt these plots.
The hole script is as follows:
setwd("E:/")
##### (1) Read data ###
dat <- read.table("Komfort_Tatsaechliche_ID_Versuchsreihe_1.txt",
header=TRUE,
sep="\t",
2005 Jul 18
1
Nested ANOVA with a random nested factor (how to use the lme function?)
Hi,
I am having trouble using the lme function to perform a nested ANOVA
with a random nested factor.
My design is as follows:
Location (n=6) (Random)
Site nested within each Location (n=12) (2 Sites nested within each
Location) (Random)
Dependent variable: sp (species abundance)
By using the aov function I can generate a nested ANOVA, however this
assumes that my nested
2007 Nov 01
2
F distribution from lme()?
Dear all,
Using the data set and code below, I am interested in modelling how egg
temperature (egg.temp)
is related to energy expenditure (kjday) and clutch size (treat) in
incubating birds using the
lme-function. I wish to generate the F-distribution for my model, and have
tried to do so using
the anova()-function. However, in the resulting anova-table, the parameter
kjday has gone from
being
2009 Apr 01
3
How to prevent inclusion of intercept in lme with interaction
Dear friends of lme,
After so many year with lme, I feel ashamed that I cannot get this to work.
Maybe it's a syntax problem, but possibly a lack of understanding.
We have growth curves of new dental bone that can well be modeled by a
linear growth curve, for two different treatments and several subjects as
random parameter. By definition, newbone is zero at t=0, so I tried to force
the
2008 Oct 15
2
Network meta-analysis, varConstPower in nlme
Dear Thomas Lumley, and R-help list members,
I have read your article "Network meta-analysis for indirect treatment
comparisons" (Statist Med, 2002) with great interest. I found it very
helpful that you included the R code to replicate your analysis;
however, I have had a problem replicating your example and wondered if
you are able to give me a hint. When I use the code from the
2003 Sep 30
0
lme vs. aov
Hi,
I have a question about using "lme" and "aov" for the
following dataset. If I understand correctly, using
"aov" with Error term in the formula is equivalent to
using "lme" with default settings, i.e. both assume
compound symmetry correlation structure. And I have
found that equivalency in the past. However, with the
follwing dataset, I got different
2003 Oct 02
0
lme vs. aov with Error term
Hi,
I have a question about using "lme" and "aov" for the
following dataset. If I understand correctly, using
"aov" with an Error term in the formula is equivalent
to using "lme" with default settings, i.e. both assume
compound symmetry correlation structure. And I have
found that equivalency in the past. However, with the
follwing dataset, I got different
2003 Apr 08
2
Basic LME
Hello R Users,
I am investigating the basic use of the LME function, using the following example;
Response is Weight, covariate is Age, random factor is Genotype
model.lme <- lme (Weight~Age, random=~ 1|Genotype)
After summary(model.lme), I find that the estimate of Age is 0.098 with p=0.758.
I am comparing the above model with the AOV function;
model.aov <- aov (Weight~Age + Genotype)
2003 Oct 01
0
lme vs. aov with Error term again
Hi all,
Sent the following question yesterday, but haven't got
any suggestions yet. So just trying again, can anyone
comment on the problem that I have? Thank you!
-------------
Hi,
I have a question about using "lme" and "aov" for the
following dataset. If I understand correctly, using
"aov" with an Error term in the formula is equivalent
to using
2005 Sep 19
1
How to mimic pdMat of lme under lmer?
Dear members,
I would like to switch from nlme to lme4 and try to translate some of my
models that worked fine with lme.
I have problems with the pdMat classes.
Below a toy dataset with a fixed effect F and a random effect R. I gave
also 2 similar lme models.
The one containing pdLogChol (lme1) is easy to translate (as it is an
explicit notation of the default model)
The more parsimonious
2004 Jun 11
2
lme newbie question
Hi
I try to implement a simple 2-factorial repeated-measure anova in the
lme framework and would be grateful for a short feedback
-my dependent var is a reaction-time (rt),
-as dependent var I have
-the age-group (0/1) the subject belongs to (so this is a
between-subject factor), and
-two WITHIN experimental conditions, one (angle) having 5, the other
3 (hands) factor-levels;
2003 Oct 02
0
RE: [S] lme vs. aov with Error term
Hi Bert,
Thanks for the suggestions. I tried lme with different
control parameters, and also tried using "ML", instaed
of "REML", but still got the same answers.
Yes, I hope some gurus on this list could give me some
hints.
Thanks
--- "Gunter, Bert" <bert_gunter at merck.com> wrote:
> But they are close. This is almost certainly a
> numeric issue --
2003 Feb 13
3
search contrasts tutorial
I'm looking for a tutorial or notes on the use of contrasts factor in
linear model in R,
I've found some mails and infos about in various documents about R,
but I've probably missed
a good review on this subject.
--
Robert Espesser
Laboratoire Parole et Langage UMR 6057, CNRS
29 Av. Robert Schuman 13621 AIX (FRANCE)
Tel: +33 (0)4 42 95 36 26 Fax: +33 (0)4 42 59 50
2007 May 24
4
Function to Sort and test AIC for mixed model lme?
Hi List
I'm running a series of mixed models using lme, and I wonder if there
is a way to sort them by AIC prior to testing using anova
(lme1,lme2,lme3,....lme7) other than by hand.
My current output looks like this.
anova
(lme.T97NULL.ml,lme.T97FULL.ml,lme.T97NOINT.ml,lme.T972way.ml,lme.T97fc.
ml, lme.T97ns.ml, lme.T97min.ml)
Model df AIC BIC logLik
2005 Feb 16
2
problem with se.contrast()
I am having trouble getting standard errors for contrasts using se.contrast() in
what appears to be a simple case to me. The following test example illustrates
my problem:
Lab <- factor(rep(c("1","2","3"),each=12))
Material <- factor(rep(c("A","B","C","D"),each=3,times=3))
Measurement <-
2001 Sep 11
2
correlation predictors problem
R colleagues,
I want
to get the correlation between the coefficients of a regression.
Everything seems OK, but when there are more than 3 regressors, the
correlation matrix is completely wrong, as follows:
> x.glm <- glm( bascule ~durP+ durI +durC+moyHzPB +moyHzIN, x,family=binomial)
> summary(x.glm,correlation=T)
Call:
glm(formula = bascule ~ durP + durI + durC + moyHzPB +
2008 Aug 17
1
before-after control-impact analysis with R
Hello everybody,
In am trying to analyse a BACI experiment and I really want to do it
with R (which I find really exciting). So, before moving on I though it
would be a good idea to repeat some known experiments which are quite
similar to my own. I tried to reproduce 2 published examples but without
much success. The first one in particular is a published dataset
analysed with SAS by
2004 Aug 10
4
Enduring LME confusion… or Psychologists and Mixed-Effects
Dear ExpeRts,
Suppose I have a typical psychological experiment that is a
within-subjects design with multiple crossed variables and a continuous
response variable. Subjects are considered a random effect. So I could model
> aov1 <- aov(resp~fact1*fact2+Error(subj/(fact1*fact2))
However, this only holds for orthogonal designs with equal numbers of
observation and no missing values.