Displaying 20 results from an estimated 300 matches similar to: "coxreg vs coxph: time-dependent treatment"
2004 Mar 17
1
What library is coxreg?
Dear mailing list,
I'm trying to run the sample program about coxreg in the eha package. But the
command is not recognized. I tried the boot and also the survival library.
Hope you can help me solve this little problem.
Thank you.
Jei
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University of the
2008 Aug 25
1
Specifying random effects distribution in glmer()
I'm trying to figure out how to carry out a Poisson regression fit to
longitudinal data with a gamma distribution with unknown shape and
scale parameters.
I've tried the 'lmer4' package's glmer() function, which fits the
Poisson regression using:
library('lme4')
fit5<- glmer(seizures ~ time + progabide + timeXprog +
offset(lnPeriod) + (1|id),
data=pdata,
2006 Jun 23
1
How to use mle or similar with integrate?
Hi
I have the following formula (I hope it is clear - if no, I can try to
do better the next time)
h(x, a, b) =
integral(0 to pi/2)
(
(
integral(D/sin(alpha) to Inf)
(
(
f(x, a, b)
)
dx
)
dalpha
)
and I want to do an mle with it.
I know how to use mle() and I also know about integrate(). My problem is
to give the parameter values a and b to the
2013 Oct 03
2
SSweibull() : problems with step factor and singular gradient
SSweibull() : problems with step factor and singular gradient
Hello
I am working with growth data of ~4000 tree seedlings and trying to fit non-linear Weibull growth curves through the data of each plant. Since they differ a lot in their shape, initial parameters cannot be set for all plants. That’s why I use the self-starting function SSweibull().
However, I often got two error messages:
2012 Feb 21
2
bootstrap in time dependent Cox model
Dear R-list,
I am wondering how to perform a bootstrap in R for the weighted time
dependent Cox model? (Andersen?Gill format, with multiple observations
from each patients) to obtain the bootstrap standard error of the
treatment effect.
Below is an example dataset. Would 'censboot' be appropriate to use in
this context? Any suggestions/references/direction to R-package will
be highly
2012 Nov 08
2
Comparing nonlinear, non-nested models
Dear R users,
Could somebody please help me to find a way of comparing nonlinear, non-nested
models in R, where the number of parameters is not necessarily different? Here
is a sample (growth rates, y, as a function of internal substrate
concentration, x):
x <- c(0.52, 1.21, 1.45, 1.64, 1.89, 2.14, 2.47, 3.20, 4.47, 5.31, 6.48)
y <- c(0.00, 0.35, 0.41, 0.49, 0.58, 0.61, 0.71, 0.83, 0.98,
2006 Jan 09
2
decide between polynomial vs ordered factor model (lme)
Dear alltogether,
two lme's, the data are available at:
http://www.anicca-vijja.de/lg/hlm3_nachw.Rdata
explanations of the data:
nachw = post hox knowledge tests over 6 measure time points (= equally
spaced)
zeitn = time points (n = 6)
subgr = small learning groups (n = 28)
gru = 4 different groups = treatment factor
levels: time (=zeitn) (n=6) within subject (n=4) within smallgroups
2009 Nov 19
1
Splitting massive output into multiple text files
Dear List,
I thought it would be much easier to put a second query into a second mail.
I need to print 426*10000 blocks of variance components data, where 426 is
the number of columns of data that have 10000 permutations of variance
generated for each of them.
I have tried printing out a smaller number of permutations for a smaller
number of markers and that has worked.
However, since a
2008 Aug 30
1
Unable to send color palette through plot.Design to method="image"
I have been trying to specify a different color palette to the image
method in plot.Design. My model has crossed two rcs() arguments and
one two-level gender argument. The goal which appears to have been
mostly achieved is to produce separate bivariate plots for men and women
The call to plot does produce a level plot but it appears only with
the default color palette despite various
2005 Mar 14
1
calling objects in a foreloop
I want to organize outputs from several regressions into a handy table. When I
try the following, each of my "fit_s" is replaces instead of read. Is there a
way to read from the regression summaries that does not require writing
separate lines of code for each?
-Ben Osborne
> fit1<-lm(dBA.spp16$sp2.dBA.ha~dBA.spp16$sp1.dBA.ha)
>
2005 Jun 15
1
anova.lme error
Hi,
I am working with R version 2.1.0, and I seem to have run into what looks
like a bug. I get the same error message when I run R on Windows as well as
when I run it on Linux.
When I call anova to do a LR test from inside a function, I get an error.
The same call works outside of a function. It appears to not find the right
environment when called from inside a function. I have provided
2008 Apr 17
1
survreg() with frailty
Dear R-users,
I have noticed small discrepencies in the reported estimate of the
variance of the frailty by the print method for survreg() and the
'theta' component included in the object fit:
# Examples in R-2.6.2 for Windows
library(survival) # version 2.34-1 (2008-03-31)
# discrepancy
fit1 <- survreg(Surv(time, status) ~ rx + frailty(litter), rats)
fit1
fit1$history[[1]]$theta
2010 Feb 26
2
Error in mvpart example
Dear all,
I'm getting an error in one of the stock examples in the 'mvpart' package. I tried:
require(mvpart)
data(spider)
fit3 <- rpart(gdist(spider[,1:12],meth="bray",full=TRUE,sq=TRUE)~water+twigs+reft+herbs+moss+sand,spider,method="dist") #directly from ?rpart
summary(fit3)
...which returned the following:
Error in apply(formatg(yval, digits - 3), 1,
2006 Aug 24
2
my error with augPred
Dear all
I try to refine my nlme models and with partial success. The model is
refined and fitted (using Pinheiro/Bates book as a tutorial) but when
I try to plot
plot(augPred(fit4))
I obtain
Error in predict.nlme(object, value[1:(nrow(value)/nL), , drop =
FALSE], :
Levels (0,3.5],(3.5,5],(5,7],(7,Inf] not allowed for
vykon.fac
>
Is it due to the fact that I have unbalanced
2011 Dec 05
1
about error while using anova function
fit1<-rq(formula=op~inp1+inp2+inp3+inp4+inp5+inp6+inp7+inp8+inp9,tau=0.15,data=wbc)
fit2<-rq(formula=op~inp1+inp2+inp3+inp4+inp5+inp6+inp7+inp8+inp9,tau=0.5,data=wbc)
fit3<-rq(formula=op~inp1+inp2+inp3+inp4+inp5+inp6+inp7+inp8+inp9,tau=0.15,data=wbc)
fit4<-rq(formula=op~inp1+inp2+inp3+inp4+inp5+inp6+inp7+inp8+inp9,tau=0.15,data=wbc)
2011 Jan 21
2
Looping with incremented object name and increment function
Folks,
I am trying to get a loop to run which increments the object name as part of
the loop. Here "fit1" "fit2" "fit3" and "fit4" are linear regression models
that I have created.
> for (ii in c(1:4)){
+ SSE[ii]=rbind(anova(fit[ii])$"Sum Sq")
+ dfe[ii]=rbind(summary(fit[ii])$df)
+ }
Error in anova(fit[ii]) : object 'fit' not found
2004 Dec 20
2
problems with limma
I try to send this message To Gordon Smyth at smyth at vehi,edu.au but it bounced
back, so here it is to r-help
I am trying to use limma, just downloaded it from CRAN. I use R 2.0.1 on Win XP
see the following:
> library(RODBC)
> chan1 <- odbcConnectExcel("D:/Data/mgc/Chips/Chips4.xls")
> dd <- sqlFetch(chan1,"Raw") # all data 12000
> #
> nzw <-
2005 Feb 14
1
testing equality of variances across groups in lme?
Hello. I am fitting a two-level mixed model which assumes equality of
variance in the lowest-level residuals across groups. The call is:
fit3<-lme(CLnNAR~CLnRGR,data=meta.analysis,
+ na.action="na.omit",random=~1+CLnRGR|study.code)
I want to test the assumption of equality of variances across groups at
the lowest level. Can someone tell me how to do this? I know that one
2004 Mar 30
0
koq.q ---- Kent O' Quigley R2
Dear R-users,
I apply to your kind attention to know if someone have used the Splus software
koq.q (Kent & O'Quigley's measure of dependence for censored data) in R and
kindly can help me.
I have tried several times to contact the authors Andrej Blejec
(andrej.blejec at uni-lj.si) or Janez Stare (janez.stare at mf.uni-lj.si) but
unfortunately no one answered me.
Following
2003 Apr 24
1
"Missing links": Hmisc and Design docs
Hi folks,
Using R Version 1.6.2 (2003-01-10)
on SuSE Linux 7.2,
I just installed Hmisc_1.5-3.tar.gz and Design_1.1-5.tar.gz
These were taken from
http://hesweb1.med.virginia.edu/biostat/s/library/r
Checked the dependencies:
Hmisc: grid, lattice, mva, acepack -- all already installed
Design: Hmisc, survival -- survival already installed, so
installed Hmisc first
All seems to go