Displaying 7 results from an estimated 7 matches for "multicenter".
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2004 Feb 04
1
xypplot (lattice): colours of lines
Using data from a multicenter study with a parallel-group design comparing
two treatments, I plotted each subject's time change of X after stratifying
for center:
xyplot(X ~ time | center, type="l", panel=panel.superpose, groups=subject)
Now I want these lines to take different colours according to the variable...
2004 Feb 05
2
xyplot (lattice): colours of lines
...ter, groups = subject,
panel = function(x, y, ...){
panel.superpose(x, y, col = treatment, type = "l", ...)
})
I get two different colours for the lines by these colours do not match the
corresponding
treatment variable
Umberto
Umberto Maggiore wrote:
Using data from a multicenter study with a parallel-group design
comparing
two treatments, I plotted each subject's time change of X after stratifying
for center:
xyplot(X ~ time | center, type="l", panel=panel.superpose, groups=subject)
Now I want these lines to take different colours according to the variable...
2013 May 12
1
Multinomial-Dirichlet using R
Hi:
I have asked this question on Cross-Validated. So it might be a cross
posting but havent received any responses to it.
I am trying to see which distribution will best fit the data I am working
on. The dataset is as following:
Site Nausea headache Abdominal Distension
1 17 5 10
2 12
2003 Oct 01
0
Power computation
Hello,
Thanks everyone who replied to my earlier Q.
I ran into a problem. I am analysng multicenter clinical trials. The model is
Y=treatment + center + treatment*center. I have the effect sizes and the
patient distributions for each scenario in the simulation.
Can someone tell me how to compute the power in this case? May be by using a
F-test or something like that.
Thank you very much.
Kr...
2011 Jul 10
1
Package "survival" --- Difference of coxph strata with subset?
[code]>require("survival")
> coxph(Surv(futime,fustat)~age + strata(rx),ovarian)
Call:
coxph(formula = Surv(futime, fustat) ~ age + strata(rx), data = ovarian)
coef exp(coef) se(coef) z p
age 0.137 1.15 0.0474 2.9 0.0038
Likelihood ratio test=12.7 on 1 df, p=0.000368 n= 26, number of events= 12
> coxph(Surv(futime,fustat)~age, ovarian, subset=rx==1)
2009 Jan 07
0
Frailty by strata interactions in coxph (or coxme)?
...that appers in the frailty term ?
Thanks in advance! I apologise for sending this as html earlier today.
Chris Argyropoulos
University of Pittsburgh Medical Center
Background
-------------
I am trying to fit a cox proportional hazards model tothe data from a two arm (treatment indicator is 0/1)
multicenter trial, adjusting for the presence of covariates and testing for the presence of a center
(and possibly a treatment X center interaction effect).
I would like to contrast the different approaches discussed in Glidden D.V. and Eric Vittinghoff. Modelling clustered survival data from multicentre clin...
2003 Oct 09
0
New Department of Biostatistics, Multiple Job Openings
...ssor, senior and junior M.S. biostatistician,
statistical programmers knowledgeable about tools such as R, S-Plus, and
LaTeX, and data managers. We are especially seeking individuals with
expertise in clinical trials, health services research, Bayesian
methods, statistical methods in epidemiology, multicenter clinical
trial data management, clinical safety assessment for pharmaceutical
trials, and modern statistical computing. Applicants for PhD or MS
biostatistician positions must have degrees in Biostatistics or have
graduate degrees in Statistics with significant experience in
clinical research or h...