Displaying 20 results from an estimated 5000 matches similar to: "nested model: lme, aov and LSMeans"
2007 Jun 05
1
Can I treat subject as fixed effect in linear model
Hi,
There are 20 subjects grouped by Gender, each subject has 2 tissues
(normal vs. cancer).
In fact, it is a 2-way anova (factors: Gender and tissue) with tissue
nested in subject. I've tried the following:
Model 1: lme(response ~ tissue*Gender, random = ~1|subject)
Model 2: response ~ tissue*Gender + subject
Model 3: response ~ tissue*Gender
It seems like Model 1 is the correct one
2010 Nov 02
2
multi-level cox ph with time-dependent covariates
Dear all,
I would like to know if it is possible to fit in R a Cox ph model with
time-dependent covariates and to account for hierarchical effects at
the same time. Additionally, I'd like also to know if it would be
possible to perform any feature selection on this model fit.
I have a data set that is composed by multiple marker measurements
(and hundreds of covariates) at different time
2008 Sep 13
2
moving from aov() to lmer()
Hello,
I've used this command to analyse changes in brain volume:
mod1<-aov(Volume~Sex*Lobe*Tissue+Error(Subject/(Lobe*Tissue)),data.vslt)
I'm comparing males/females. For every subject I have 8 volume measurements
(4 different brain lobes and 2 different tissues (grey/white matter)).
As aov() provides only type I anovas, I would like to use lmer() with type
II, however, I have
2011 Sep 20
1
A question regarding random effects in 'aov' function
Hi,
I am doing an analysis to see if these is tissue specific effects on the
gene expression data .
Our data were collected from 6 different labs (batch effects). lab 1 has
tissue type 1 and tissue type 2, lab 2 has tissue 3, 4,5,6. The other labs
has one tissue type each. The 'sample' data is as below:
2008 Sep 14
2
Help please! How to code a mixed-model with 2 within-subject factors using lme or lmer?
Hello,
I'm using aov() to analyse changes in brain volume between males and
females. For every subject (there are 331 in total) I have 8 volume
measurements (4 different brain lobes and 2 different tissues
(grey/white matter)). The data looks like this:
Subject Sex Lobe Tissue Volume
subect1 1 F g 262374
subect1 1 F w 173758
subect1 1 O g 67155
subect1 1 O w 30067
subect1 1 P g 117981
2004 Jul 21
2
RE: Comparison of correlation coefficients - Details
Dear all
I apologize for cross-posting, but first it is accepted custom to
thank the repliers and give a summary, and second I have still
the feeling that this problem might be a general statistical problem
and not necessarily related to microarrays only, but I might be wrong.
First, I want to thank Robert Gentleman, Mark Kimpel and Mark Reiners
for their kind replies. Robert Gentleman kindly
2008 Jan 22
1
anova function to test the difference between two coefficients in nlme package
Dear Dr. Bates, and R-help,
I've tried the anova function to test the difference between two
coefficients, as shown on page 225 of your book "Mixed Effects Models
in S and S-Plus (Statistics and Computing)".
When I type: anova( fm2BW.lme, L = c(TimeDiet2 = 1, TimeDiet3 = -1) )
I got the following error message:
Error: unexpected '=' in "anova( fm2BW.lme, L =
2011 Oct 30
1
Normality tests on groups of rows in a data frame, grouped based on content in other columns
Dear R users,
I have a data frame in the form below, on which I would like to make normality tests on the values in the ExpressionLevel column.
> head(df)
ID Plant Tissue Gene ExpressionLevel
1 1 p1 t1 g1 366.53
2 2 p1 t1 g2 0.57
3 3 p1 t1 g3 11.81
4 4 p1 t2 g1 498.43
5 5 p1 t2 g2 2.14
6 6 p1 t2 g3 7.85
I
2010 Nov 25
1
difficulty setting the random = argument to lme()
My small brain is having trouble getting to grips with lme()
I wonder if anyone can help me correctly set the random = argument
to lme() for this kind of setup with (I think) 9 variance/covariance
components ...
Study.1 Study.2 ...
Study.10
Treatment.A: subject: 1 2 3 4 5 6 etc. 28 29 30
Treatment.B: subject: 31
2008 Feb 21
3
variable syntax problem
dear members,
i would like to write a variable in a plot title (main="") but i don't
know the right syntax:(...i tried a lot of different ways without success.
here my example:
y=30
z=33
for (i in 10:length(tissue)) {
png(filename = tissues[i], width = 1024, height = 768, pointsize = 12,
bg = "white")
gene.graph("ENSG00000115252", rma.affy, gps=list(1:3,
2011 Sep 15
1
Questions on 'lme' function, urgent!
Hi Dear all,
I have some gene expression data samples from different tissue types
-----------------------------------------------
- 120 samples from blood (B)
- 20 samples from Liver (L)
- 15 samples from Kidney (K)
- 6 samples from heart (H)
-----------------------------------------------
All the samples are from different individuals, so there are in total 161
individuals from which the DNA was
2010 Jan 29
1
help on drawing right colors within a grouped xyplot (Lattice)
Hi,
I've lost my mind on it... I have to scatterplot two vectors, grouped by a third variable, with two different dimensions according to whether each cell line in the plot is sensitive or resistant to a given drug, and with a different color for each of 9 tissues of origin.
Here's what I've done:
2010 Apr 23
2
Problem with parsing a dataset - help earnestly sought
Dear fellow R-help members,
I hope to seek your advice on how to parse/manage a dataset with hundreds of
columns. Two examples of these columns, 'cancer.problems', and
'neuro.problems' are depicted below. Essentially, I need to parse this into
a useful dataset, and unfortunately, I am not familiar with perl or any such
language.
data <- data.frame(id=c(1:10))
2007 Nov 13
1
Cleaning database: grep()? apply()?
Dear R users,
I have a huge database and I need to adjust it somewhat.
Here is a very little cut out from database:
CODE NAME DATE DATA1
4813 ADVANCED TELECOM 1987 0.013
3845 ADVANCED THERAPEUTIC SYS LTD 1987 10.1
3845 ADVANCED THERAPEUTIC SYS LTD 1989 2.463
3845 ADVANCED THERAPEUTIC SYS LTD 1988 1.563
2836 ADVANCED TISSUE
2009 Feb 20
1
lm and aov produce different results for nested fixed-factor anova
Dear R users,
I have trouble obtaining the same results for nested Anova with two fixed factors when using lm and aov functions.
The formulas are:
> e1=aov(y~x/z)
> e2=lm(y~x/z)
summary(e1)
Df Sum Sq Mean Sq F value Pr(>F)
x 47 260.0 5.5 18.0088 < 2.2e-16 ***
x:z 195 169.6 0.9 2.8318 < 2.2e-16 ***
Residuals 14425
2011 May 20
1
How to do covariate adjustment in R
Hi, I have a question about how to do covariate adjustment.
I have two sets of 'gene expression' data. They are from two different
tissue types, 'liver' and 'brain', respectively.
The purpose of my analysis is to compare the pattern of the whole genome
'gene expression' between the two tissue types.
I have 'age' and 'sex' as covariates. Since
2009 Dec 17
1
Help with Merge - unexpected loss of factor level
Hi, Thanks in advance for any advice you can give me, I am very stumped on this problem...
I use R every day and consider myself a confident user, but this seems to be an elementary problem..
Outline of problem: I am analysing the results of a study on protein expression in cancer tissues. I have raw intensities from 2 different types of cancer and normal tissue, which can be taken from several
2005 Feb 10
5
sample
I am trying to sample a subset from a matrix using sample.
The size of the matrix is 20X 1532. It works fine with this,
but when I transpose the matrix and try to sample it, it returns
null.
pick.set<-sample(tissue.exp.t,5,replace=FALSE,prob=NULL)
Is there something that I am missing here ?
Thanks ../Murli
2007 Jun 20
2
"xtable" results doesn't correspond to data.frame
Dear useRs,
Am trying to use xtable on the following data.frame and I don't get what I
expect:
example.table <- data.frame(rbind(
c("Gender"," "," "," "),
cbind(rep(" ",2),c("Male","Female"),c(3.0,4.0),c(3/7,4/7))
))
colnames(example.table) <- c(" "," ","number of
2009 Oct 15
2
Proper syntax for using varConstPower in nlme
Hello,
Excuse me for posting two questions in one day, but I figured it would be
better to ask my questions in separate emails. I will again give the caveat
that I'm not a statistician by training, but have a fairly decent
understanding of probability and likelihood.
As before, I'm trying to fit a nonlinear model to a dataset which has two main
factors using nlme. Within the dataset