Displaying 20 results from an estimated 2000 matches similar to: "survreg function in survival package"
2011 May 14
2
Survreg object
Hi,Just a quick one, does anyone know the command for accessing the standard errors from a survreg object? I can access the coefficients by model$coefficients, but I cant seem to find a command to access the errors. Any help would be greatly appreciated.Regards,Andre
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2006 Apr 25
5
Heteroskedasticity in Tobit models
Hello,
I've had no luck finding an R package that has the ability to estimate a
Tobit model allowing for heteroskedasticity (multiplicative, for example).
Am I missing something in survReg? Is there another package that I'm
unaware of? Is there an add-on package that will test for
heteroskedasticity?
Thanks for your help.
Cheers,
Alan Spearot
--
Alan Spearot
Department of Economics
2005 Nov 27
1
the output of coxph
Dear All:
I have some questions about the output of coxph.
Below is the input and output:
----------------------------------------
> coxph(formula = Surv(futime, fustat) ~ age + rx + ecog.ps, data =
+ ovarian, x = TRUE)
Call:
coxph(formula = Surv(futime, fustat) ~ age + rx + ecog.ps, data =
ovarian, x = TRUE)
coef exp(coef) se(coef) z p
age 0.147 1.158
2003 Feb 27
2
interval-censored data in survreg()
I am trying to fit a lognormal distribution on interval-censored
data. Some of my intervals have a lower bound of zero.
Unfortunately, it seems like survreg() cannot deal with lower
bounds of zero, despite the fact that plnorm(0)==0 and
pnorm(-Inf)==0 are well defined. Below is a short example to
reproduce the problem.
Does anyone know why survreg() must behave that way?
Is there an alternate
2009 Feb 06
1
Using subset in validate() in Design, what is the correct syntax?
Hi
I am trying to understand how to get the validate() function in Design
to work with the subset option. I tried this:
ovarian.cph=cph(Surv(futime, fustat) ~ age+factor(ecog.ps)+strat(rx),
time.inc=1000, x=T, y=T, data=ovarian)
validate(ovarian.cph)
#fine when no subset is used, but the following two don't work:
> validate(ovarian.cph, subset=ovarian$ecog.ps==2)
Error in
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
2007 Dec 07
1
Make natural splines constant outside boundary
Hi,
I'm using natural cubic splines from splines::ns() in survival
regression (regressing inter-arrival times of patients to a queue on
queue size). The queue size fluctuates between 3600 and 3900.
I would like to be able to run predict.survreg() for sizes <3600 and
>3900 by assuming that the rate for <3600 is the same as for 3600 and
that for >4000 it's the same as for
2009 Feb 25
3
survival::survfit,plot.survfit
I am confused when trying the function survfit.
my question is: what does the survival curve given by plot.survfit mean?
is it the survival curve with different covariates at different points?
or just the baseline survival curve?
for example, I run the following code and get the survival curve
####
library(survival)
fit<-coxph(Surv(futime,fustat)~resid.ds+rx+ecog.ps,data=ovarian)
2005 Sep 13
1
coxph.detail() does not work
Hello everyone,
I tried to use coxph.detail() to get the hazard function. But a warning
messge always returns to me, even in the example provided by its help
document:
> ?coxph.detail
> fit <- coxph(Surv(futime,fustat) ~ age + rx + ecog.ps, ovarian, x=TRUE)
> fitd <- coxph.detail(fit)
Warning message:
data length [37] is not a sub-multiple or multiple of the number of
rows
2009 Mar 30
1
Possible bug in summary.survfit - 'scale' argument ignored?
Hi all,
Using:
R version 2.8.1 Patched (2009-03-07 r48068)
on OSX (10.5.6) with survival version:
Version: 2.35-3
Date: 2009-02-10
I get the following using the first example in ?summary.survfit:
> summary( survfit( Surv(futime, fustat)~1, data=ovarian))
Call: survfit(formula = Surv(futime, fustat) ~ 1, data = ovarian)
time n.risk n.event survival
2006 Dec 21
1
: newbie estimating survival curve w/ survfit for coxph
I am wondering how to estimate the survival curve for a particular case(s)
given a coxph model
using this example code:
#fit a cox proportional hazards model and plot the
#predicted survival curve
fit <- coxph(
Surv(futime,fustat)~resid.ds+strata(rx)+ecog.ps+age,data=ovarian[1:23,])
z <- survfit(fit,newdata=ovarian[24:26,],individual=F)
zs <- z$surv
zt <-
2012 Jun 28
3
Sobre survival analysis
Hola
Estoy tratando de correr un survival analysis usando un Cox regression model.
Tengo una duda respecto a la organizacion del script. Tengo una variable que es -tamano del individuo- y quiero ver si hay diferencia en sobrevivencia respecto a tamano. Como diseno de campo los tamanos fueron ubicados de forma aleatoria en bloques al azar.
Cuado planteo el script tengo algo como:
2008 Oct 28
2
Fitting weibull and exponential distributions to left censoring data
Dear R-users
I have some datasets, all left-censoring, and I would like to fit
distributions to (weibull,exponential, etc..). I read one solution using the
function survreg in the survival package. i.e
survreg(Surv(...)~1, dist="weibull") but it returns only the scale
parameter.
Does anyone know how to successfully fit the exponential, weibull etc...
distributions to left-censoring
2007 Jan 23
1
Estimate and plot hazard function using "muhaz" package
Dear R users,
I am trying to use "muhaz" and "plot.muhaz" functions in "muhaz" package to
estimate and plot hazard funciton. However function "muhaz" always gives
error message "Error in Surv(times, delta) : object "times" not found". I
could not even run their sample codes in the user's manual as follows:
data(ovarian)
2007 May 16
2
log rank test p value
How can I get the Log - Rank p value to be output?
The chi square value can be output, so I was thinking if I can also have the
degrees of freedom output I could generate the p value, but can't see how to
find df either.
> (survtest <- survdiff(Surv(time, cens) ~ group, data = surv,rho=0))
Call:
survdiff(formula = Surv(time, cens) ~ group, data = surv, rho = 0)
N Observed
2018 May 24
1
Predictions from a Cox model - understanding centering of binary/categorical variables
Dear all,
I am using R 3.4.3 on Windows 10. I am preparing some teaching materials and I'm having trouble matching the by-hand version with the R code.
I have fitted a Cox model - let's use the ovarian data as an example:
library(survival)
data(ovarian)
ova_mod <- coxph(Surv(futime,fustat)~age+rx,data=ovarian)
If I want to make predict survival for a new set of individuals at 100
2011 Jun 24
1
UnoC function in survAUC for censoring-adjusted C-index
Hello,
I am having some trouble with the 'censoring-adjusted C-index' by Uno et al, in the package survAUC. The relevant function is UnoC.
The question has to do with what happens when I specify a time point t for the upper limit of the time range under consideration (we want to avoid using the right-end tail of the KM curve).
Copying from the example in the help file:
TR <-
2004 Dec 06
1
The survival rate at a certain time
Hello there,
I am doing analysis on survival data. How do I pick out a probability of
survival at a chosen landmark time(for example, 3 years, 4 years) from
the result of "survfit"? or any other functions? As I know, the result
of 'survfit' only have the probabilities for all event or cencor time.
Thank you very much
Lisa Wang
Princess Margaret Hospital
Toronto, Ca
tel:
2011 Oct 01
4
Is the output of survfit.coxph survival or baseline survival?
Dear all,
I am confused with the output of survfit.coxph.
Someone said that the survival given by summary(survfit.coxph) is the
baseline survival S_0, but some said that is the survival S=S_0^exp{beta*x}.
Which one is correct?
By the way, if I use "newdata=" in the survfit, does that mean the survival
is estimated by the value of covariates in the new data frame?
Thank you very much!
2001 Feb 22
3
[newbie] Cox Baseline Hazard
Hello everybody.
First of all, I would like to present myself.
I'm a french student in public health and I like statistics though I'm
not that good in mathematics (but I try to catch up). I've discovered R
recently while trying to find a statistical program in order to avoid
rebooting my computer under windows when I need to do some statistical
work.
And here is my first question.