Displaying 20 results from an estimated 20000 matches similar to: "(Meta-analysis) How to build|fake a [n]lm[e] object ?"
2006 Nov 09
2
Meta-regression with lmer() ? If so, how ?
Dear List,
I am (again) looking at meta-regression as a way to refine meta-analytic
results. What I want to do is to assess the impact of some fixed factors
on the results of a meta-analysis. Some of them may be crossed with the
main factor of the meta-analysis (e. g. clinical presentation of a
disease, defining subgroups in each of the studies under analysis), some
of them may be a grouping
2007 Nov 26
1
Unweighted meta-analysis
Hello
I'm very much a beginner on meta-analysis, so apologies if this is a
trivial posting. I've been sent a set data from separate experimental
studies, Treatment and Control, but no measure of the variance of effect
sizes, numbers of replicates etc. Instead, for each study, all I have
is the mean value for the treatment and control (but not the SD). As
far as I can tell, this forces
2012 Mar 28
0
Major update: meta version 2.0-0
Version 2.0-0 of meta (an R package for meta-analysis) is now available
on CRAN. Changes are described below.
Yours,
Guido
Major revision
R package meta linked to R package metafor by Wolfgang Viechtbauer to
provide additional statistical methods, e.g. meta-regression and other
estimates for tau-squared (REML, ...)
New functions:
- metareg (meta-regression)
- metabias
2012 Mar 28
0
Major update: meta version 2.0-0
Version 2.0-0 of meta (an R package for meta-analysis) is now available
on CRAN. Changes are described below.
Yours,
Guido
Major revision
R package meta linked to R package metafor by Wolfgang Viechtbauer to
provide additional statistical methods, e.g. meta-regression and other
estimates for tau-squared (REML, ...)
New functions:
- metareg (meta-regression)
- metabias
2008 Aug 22
0
Re : Help on competing risk package cmprsk with time dependent covariate
Hello again,
I m trying to use timereg package as you suggested (R2.7.1 on XP Pro).
here is my script based on the example from timereg for a fine & gray model in which
relt = time to event, rels = status 0/1/2 2=competing, 1=event of interest, 0=censored
random = covariate I want to test
library(timereg)
rel<-read.csv("relapse2.csv", header = TRUE, sep = ",",
2004 Aug 13
0
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m.eds from u-s_a & 0v_ernig'ht sh,ipping
http://k.l.123a2zrx.us
It would be a out and out day-dreaming if you don't want to lose weight via
exercise? Now Maridia is with you,you can be a day-dreamer.
Again the scene changed, and within a dingy, underground room, hemmed in by
walls of stone, and dimly lighted by a
2010 Sep 23
2
Error: attempt to apply non-function
This code worked fine for me, then did some cleaning up of formatting using ESS (Emacs) and now I get this error, no idea what is causing it, all the brackets/parentheses seem to be balanced. What have I done wrong?
Thanks
Jim
p0.trial01 <- 0.25
TruOR01 <- 0.80
num.patients.01 <- 50
num.trials.01 <- 5
LOR01.het.in <- 0.00
num.sims <- 1
simLOR01 <-
2009 Jul 26
1
Assessing standard errors of polynomial contrasts
Hi, using polynomial contrasts for the ordered factors in an experiment
leads to much nicer covariance structure than using treatment contrasts. It
is easy to assess the mean effect for each of the experimental groups.
However, standard errors are provided only for the components of the
orthogonal contrasts. I wonder how to assess the standard errors not of the
components, but of the respective
2008 Aug 22
1
Help on competing risk package cmprsk with time dependent covariate
Dear R users,
I d like to assess the effect of "treatment" covariate on a disease relapse risk with the package cmprsk.
However, the effect of this covariate on survival is time-dependent
(assessed with cox.zph): no significant effect during the first year of follow-up,
then after 1 year a favorable effect is observed on survival (step
function might be the correct way to say that ?).
2017 Jun 26
0
Model studies in one analysis using treatment as a five level moderator in a meta-regression
hi Jay,
Consult a local statistician. Statistics is not you think is (namely
simple computations, R and probably plotting..).
regards,
vito
Jay Zola <jayjay.1988 at hotmail.nl> ha scritto:
> Hello,
>
>
> I am medical student, writing a meta-analysis on complication and
> reoperation rates after the five most common treatments of distal
> radius fractures. I have
2008 Aug 20
0
cmprsk and a time dependent covariate in the model
Dear R users,
I d like to assess the effect of "treatment" covariate on a disease relapse risk with the package cmprsk.
However, the effect of this covariate on survival is time-dependent
(assessed with cox.zph): no significant effect during the first year of follow-up,
then after 1 year a favorable effect is observed on survival (step
function might be the correct way to say that
2009 Aug 31
1
GLM contrasting question
I have run a glm with a final formula of : (dependent variable = parasite
load, main effects are sex, month, length and weight, with sex:month and
length:weight first order interactions).
I am using the summary(mod) command to give me the contrasts, which I
believe use the contr.treatment command. I do not have a treatment group as
such as I am comparing data from a wild system so I use the
2003 Nov 01
4
Beginner: Homogenity of Variances
Hello,
for my meta-analysis I try to test if two varainces are equal without
using the raw scores. I have is the SD's, N's and the Means.
I want to test the variances from dependent and independend
samples.
I assume I can use the var.test procedure for the independent
samples, but what about the dependent samples ? Has anyone an
idea how to realise this with R ?
Thanks in advance
2003 Feb 26
2
na.action in model.tables and TukeyHSD
Hello everybody!
I use R 1.6.2 in Windows, and have a problem controlling the na.action.
In a dataset with twelve trials, one of the trials lack any readings of the variable "STS.SH" (standing power at harvest)
Fitting an aov() object with the call:
led1t7sts.aov <- aov(STS.SH ~ Trial/Block + Treatment + Treatment:Trial, data = led1t7, na.action=na.exclude)
seems to work as it
2017 Jun 26
3
Model studies in one analysis using treatment as a five level moderator in a meta-regression
Hello,
I am medical student, writing a meta-analysis on complication and reoperation rates after the five most common treatments of distal radius fractures. I have been busy with the statistics for months by my self, but find it quite hard since our classes were very basic. Now I want to compare the treatment modalities to see if there are significant differences. Using R I was able to
2017 Jun 26
1
Model studies in one analysis using treatment as a five level moderator in a meta-regression
Dear Vito,
Thank you for your reply. I tried to contact the statistics departement numerous times, but did not receive any reply. That is why I started to look on the internet for help.
Yours sincerely,
Jay
Verstuurd vanaf mijn iPhone
> Op 26 jun. 2017 om 22:05 heeft Vito Michele Rosario Muggeo <vito.muggeo at unipa.it> het volgende geschreven:
>
> hi Jay,
> Consult a local
2009 Jan 07
0
Frailty by strata interactions in coxph (or coxme)?
Hello,
I was hoping that someone could answer a few questions for me (the background is given below):
1) Can the coxph accept an interaction between a covariate and a frailty term
2) If so, is it possible to
a) test the model in which the covariate and the frailty appear as main terms using the penalized likelihood (for gaussian/t frailties)
b)augment model 1) by stratifying on the variable that
2009 Oct 26
1
explalinig the output of my linear model analysis
Hi,
I am new in statistics and i manage to make the linear model analysis but i
have some difficulties in explaining the results. Can someone help me
explalinig the output of my linear model analysis ? My data are with 2
variables habitat (e,s) and treatment (a,c,p) with multiple trials within.
Thank you in advance
Call:
lm(formula = a$wild ~ a$habitat/a$treatment/a$trial)
Residuals:
Min
2012 Feb 19
1
coxme: model simplification using LR-test?
Hi
I'm encountering some problems with coxme
My data:
I'm looking at the survival of animals in an experiment with 3 treatments,
which came from 4 different populations, two of which were infected with a
parasite and two of which were not. I'm interested if infected animals
differe from uninfected ones across treatments.
Factor 1: treatment (3 levels)
Factor 2: infection state
2009 Mar 06
1
a general question
Hi everyone,
Although this question is more related to ChIP and ChIP-seq, it could be
probably anchored in a more general statistical context.
The question is : what method is better to assess the significance of the
change in a signal (the signal can be DNA binding, for instance) given the
background and 2 conditions.
<. condition1 (eg no treatment) : background = 1;