Displaying 20 results from an estimated 300 matches similar to: "Nested ANOVA with a random nested factor (how to use the lme function?)"
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",
2001 Dec 23
1
aov for mixed model (fixed and random)?
I'm starting to understand fixed and random effects, but I'm
puzzled a bit. Here is an example from Hays's textbook (which is
great at explaining fixed vs. random effects, at least to dummies
like me), from the section on mixed models. You need
library(nlme) in order to run it.
------
task <- gl(3,2,36) # Three tasks, a fixed effect.
subj <- gl(6,6,36) # Six subjects, a random
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
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
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
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
2004 Jul 16
1
Fixed and random factors in aov()
Hi,
I'm confused about how to specify random and fixed factors in an aov()
term. I tried to reproduce a textbook example: One fixed factor (Game, 4
levels) and one random factor (Store, 12 levels), response is Points.
The random factor Store is nested in Game. I tried
> str(kh.df)
`data.frame': 48 obs. of 4 variables:
$ Subj : Factor w/ 48 levels
2012 Sep 14
1
linear mixed-effects models with two random variables?
Dear R users,
Does anyone knows how to run a glmm with one fixed factor and 2 random
numeric variables (indices)? Is there any way to force in the model a
separate interaction of those random variables with the fixed one?
I hope you can help me.
#eg.
Reserve <- rep(c("In","Out"), 100)
fReserve <- factor(Reserve)
DivBoulders <- rep
2006 Jan 31
1
lme in R (WinXP) vs. Splus (HP UNIX)
R2.2 for WinXP, Splus 6.2.1 for HP 9000 Series, HP-UX 11.0.
I am trying to get a handle on why the same lme( ) code gives
such different answers. My output makes me wonder if the
fact that the UNIX box is 64 bits is the reason. The estimated
random effects are identical, but the fixed effects are very
different. Here is my R code and output, with some columns
and rows deleted for space
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.
2011 Feb 03
0
Need advises on mixed-effect model ( a concrete example)
Dear R-help members,
I'm trying to run LME model on some behavioral data and need
confirmations about what I'm doing...
Here's the story...
I have some behavioral reaction time (RT) data (participants have to
detect dome kind of auditory stimuli). the dependant variable is RT
measured in milliseconds. 61 participants were tested separated in 4 age
groups (unblanced groups,
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
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 ~
2004 Aug 11
1
Fwd: Enduring LME confusion… or Psychologists and Mixed-Effects
In my undertstanding of the problem, the model
lme1 <- lme(resp~fact1*fact2, random=~1|subj)
should be ok, providing that variances are homogenous both between &
within subjects. The function will sort out which factors &
interactions are to be compared within subjects, & which between
subjects. The problem with df's arises (for lme() in nlme, but not in
lme4), when
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)
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;
2008 Jan 28
0
(no subject)
Hi all
I am trying to generate a normal unbalanced data to estimate the coefficients of LM, LMM, GLM, and GLMM and their standard errors. Also, I am trying to estimate the variance components and their standard errors. Further, I am trying to use the likelihood ratio test to test H0: sigma^2_b = 0 (random effects variance component), and the t-test to test H0:mu=0 (intercept of the model Yij = mu
2011 Oct 04
1
Question about linear mixed effects model (nlme)
Hi,
I applied a linear mixed effect model in my data using the nlme package.
lme2<-lme(distance~temperature*condition, random=~+1|trial, data) and then
anova.
I want to ask if it is posible to get the least squares means for the
interaction effect and the corresponding 95%ci. And then plot this values.
Thank you
Panagiotis
--
View this message in context:
2007 Apr 11
0
Error with corCompSymm and lme fit for repeated measures
Dear R Friends,
I need help with an error associated with corCompSymm in an lme fit.
I am using a mixed effects model to analyze a split-plot with
repeated measures and would like to fit with the compound symmetry
correlation structure. This problem doesn't occur when using
corAR1 or any of the other structures. I would greatly appreciate
help on how to solve this issue.
Here's my