Displaying 20 results from an estimated 400 matches similar to: "How to plot survival data from multiple trials (simulations)?"
2008 May 06
2
NLS plinear question
Hi All.
I've run into a problem with the plinear algorithm in nls that is confusing
me.
Assume the following reaction time data over 15 trials for a single unit.
Trials are coded from 0-14 so that the intercept represents reaction time in
the first trial.
trl RT
0 1132.0
1 630.5
2 1371.5
3 704.0
4 488.5
5 575.5
6 613.0
7 824.5
8 509.0
9
2012 May 26
2
Assessing interaction effects in GLMMs
Dear R gurus
I am running a GLMM that looks at whether chimpanzees spend time in shade
more than sun (response variable 'y': used cbind() on counts in the sun and
shade) based on the time of day (Time) and the availability of shade
(Tertile). I've included some random factors too which are the chimpanzee
in question (Individual) and where they are in a given area (Zone). There
are
2009 May 24
3
[LLVMdev] mixing static/dynamic code
Hi,
I have the following code, the lines preceded by `>` being added at runtime
(the snipped was also printed at runtime)
define i32 @myfunc(i32 %pi) {
entry:
%pi_addr = alloca i32 ; <i32*> [#uses=3]
%retval = alloca i32 ; <i32*> [#uses=2]
%tmp = alloca i32 ; <i32*> [#uses=2]
> %ptr32 = alloca i32
2009 Sep 08
1
Obtaining value of median survival for survfit function to use in calculation
Hi,
I'm sure this should be simple but I can't figure it out! I want to get the median survival calculated by the survfit function and use the value rather than just be able to print it. Something like this:
library(survival)
data(lung)
lung.byPS = survfit(Surv (time, status) ~ ph.ecog, data=lung)
# lung.byPS
Call: survfit(formula = Surv(time, status) ~ ph.ecog, data = lung)
1
2009 Aug 01
2
Cox ridge regression
Hello,
I have questions regarding penalized Cox regression using survival
package (functions coxph() and ridge()). I am using R 2.8.0 on Ubuntu
Linux and survival package version 2.35-4.
Question 1. Consider the following example from help(ridge):
> fit1 <- coxph(Surv(futime, fustat) ~ rx + ridge(age, ecog.ps, theta=1), ovarian)
As I understand, this builds a model in which `rx' is
2012 Jun 05
1
model.frame and predvars
I was looking at how the model.frame method for lm works and comparing
it to my own for coxph.
The big difference is that I try to retain xlevels and predvars
information for a new model frame, and lm does not.
I use a call to model.frame in predict.coxph, which is why I went that
route, but never noted the difference till now (preparing for my course
in Nashville).
Could someone shed light
2009 May 24
0
[LLVMdev] mixing static/dynamic code
Paul Martin wrote:
> Hi,
> I have the following code, the lines preceded by `>` being added at
> runtime (the snipped was also printed at runtime)
>
> define i32 @myfunc(i32 %pi) {
> entry:
> %pi_addr = alloca i32 ; <i32*> [#uses=3]
> %retval = alloca i32 ; <i32*> [#uses=2]
> %tmp = alloca i32 ;
2008 Mar 03
1
Problem plotting curve on survival curve
Calum had a long question about drawing survival curves after fitting a Weibull
model, using pweibull, which I have not reproduced.
It is easier to get survival curves using the predict function. Here is a
simple example:
> library(survival)
> tfit <- survreg(Surv(time, status) ~ factor(ph.ecog), data=lung)
> table(lung$ph.ecog)
0 1 2 3 <NA>
63 113 50 1
2009 Nov 13
2
survreg function in survival package
Hi,
Is it normal to get intercept in the list of covariates in the output of survreg function with standard error, z, p.value etc? Does it mean that intercept was fitted with the covariates? Does Value column represent coefficients or some thing else?
Regards,
-------------------------------------------------
tmp = survreg(Surv(futime, fustat) ~ ecog.ps + rx, ovarian,
2009 May 24
2
[LLVMdev] mixing static/dynamic code
Nick,
Thanks for the quick answer.
Dereferencing the pointer does yield the same result in both cases but
that's not what I want to do. I want to instrument the program dynamically
and keep track of certain memory locations which is a problem if the same
variable has different addresses for the static/dynamic code - as far I see
this is what it's happening but I have no clue why.
Paul
On
2009 Feb 06
1
Using subset in validate() in Design, what is the correct syntax?
Hi
I am trying to understand how to get the validate() function in Design
to work with the subset option. I tried this:
ovarian.cph=cph(Surv(futime, fustat) ~ age+factor(ecog.ps)+strat(rx),
time.inc=1000, x=T, y=T, data=ovarian)
validate(ovarian.cph)
#fine when no subset is used, but the following two don't work:
> validate(ovarian.cph, subset=ovarian$ecog.ps==2)
Error in
2011 Jan 24
1
How to measure/rank ?variable importance when using rpart?
--- included message ----
Thus, my question is: *What common measures exists for ranking/measuring
variable importance of participating variables in a CART model? And how
can
this be computed using R (for example, when using the rpart package)*
---end ----
Consider the following printout from rpart
summary(rpart(time ~ age + ph.ecog + pat.karno, data=lung))
Node number 1: 228 observations,
2005 Nov 27
1
the output of coxph
Dear All:
I have some questions about the output of coxph.
Below is the input and output:
----------------------------------------
> coxph(formula = Surv(futime, fustat) ~ age + rx + ecog.ps, data =
+ ovarian, x = TRUE)
Call:
coxph(formula = Surv(futime, fustat) ~ age + rx + ecog.ps, data =
ovarian, x = TRUE)
coef exp(coef) se(coef) z p
age 0.147 1.158
2010 Feb 16
1
survival - ratio likelihood for ridge coxph()
It seems to me that R returns the unpenalized log-likelihood for the ratio likelihood test when ridge regression Cox proportional model is implemented. Is this as expected?
In the example below, if I am not mistaken, fit$loglik[2] is unpenalized log-likelihood for the final estimates of coefficients. I would expect to get the penalized log-likelihood. I would like to check if this is as expected.
2009 May 24
0
[LLVMdev] mixing static/dynamic code
Paul Martin wrote:
>
> Nick,
> Thanks for the quick answer.
> Dereferencing the pointer does yield the same result in both cases but
> that's not what I want to do. I want to instrument the program
> dynamically and keep track of certain memory locations which is a
> problem if the same variable has different addresses for the
> static/dynamic code - as far I see
2003 Feb 27
2
interval-censored data in survreg()
I am trying to fit a lognormal distribution on interval-censored
data. Some of my intervals have a lower bound of zero.
Unfortunately, it seems like survreg() cannot deal with lower
bounds of zero, despite the fact that plnorm(0)==0 and
pnorm(-Inf)==0 are well defined. Below is a short example to
reproduce the problem.
Does anyone know why survreg() must behave that way?
Is there an alternate
2009 Sep 02
1
a question for beginner
Hello,
i have this dataset http://www.umass.edu/statdata/statdata/data/pharynx.txt.
the variables GRADE, T_STAGE anda N_STAGE are qualitative or quantitative
variables???
i only have this simple doubt...!
another example: why in the dataset ovarian (library survival) the variable
ecog.ps: ECOG performance status (1 is better, see reference) it is
consider quantitative?
Thank's for
2014 Jul 05
1
Predictions from "coxph" or "cph" objects
Dear R users,
My apologies for the simple question, as I'm starting to learn the concepts
behind the Cox PH model. I was just experimenting with the survival and rms
packages for this.
I'm simply trying to obtain the expected survival time (as opposed to the
probability of survival at a given time t). I can't seem to find an option
from the "type" argument in the predict
2009 May 24
1
[LLVMdev] mixing static/dynamic code
Nick,
Your solution works well if there is a store instruction in the function but
in the case where there is none (i.e. the argument is passed on directly to
another function), creating a store does not help to get the memory address
of the variable which takes me back to my initial question at
http://lists.cs.uiuc.edu/pipermail/llvmdev/2009-May/022590.html - isn't
there a way to obtain the
2010 Mar 05
2
Defining a method in two packages
The coxme package has a ranef() method, as does lme4. I'm having
trouble getting them to play together, as shown below. (The particular
model in the example isn't defensible, but uses a standard data set.)
The problem is that most of the time only one of lme4 or coxme will be
loaded, so each needs to define the basic ranef function as well as a
method for it. But when loaded together