, 2005 1:19 AM
Subject: Re: [R] Coxph with factors
On Sat, 16 Jul 2005, Thomas Lumley wrote:
Yes, but you don't need to go via the baseline. The survival curves for
any two covariate vectors z1 and z2 are related by
S(t; z1)= S(t; z2)^(z1-z2)
Actually
S(t; z1)=S(t;z2) ^(beta'(z1-z2
)+).
And then proceeding as mention in the above paragraph (clearly not an
efficient way of doing things).
- Original Message -
From: Thomas Lumley [EMAIL PROTECTED]
To: Kylie-Anne Richards [EMAIL PROTECTED]
Cc: r-help@stat.math.ethz.ch
Sent: Saturday, July 16, 2005 12:31 AM
Subject: Re: [R] Coxph
On Sat, 16 Jul 2005, Kylie-Anne Richards wrote:
Thank you for your help.
In any case, to specify f.pom You need it to be a factor with the same set
of levels. You don't say what the lowest level of pom is, but if it is,
say, -3.
On Sat, 16 Jul 2005, Thomas Lumley wrote:
Yes, but you don't need to go via the baseline. The survival curves for
any two covariate vectors z1 and z2 are related by
S(t; z1)= S(t; z2)^(z1-z2)
Actually
S(t; z1)=S(t;z2) ^(beta'(z1-z2))
of course.
-thomas
Yes, and please show us a reproducible example or small section of the
data as well as the error output.
On Thu, 2005-07-14 at 15:36 +, Dieter Menne wrote:
Kylie-Anne Richards kar at itga.com.au writes:
I am fitting a coxph model with factors. I am running into problems when
using
ramasamy at cancer.org.uk
Fri Jul 15 09:58:19 CEST 2005
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On Fri, 15 Jul 2005, Kylie-Anne Richards wrote:
FIRST Q: The default uses the mean of 'vo' and mean of 'po', but what is it
using for the factors?? Is it the sum of the coef of the factors divided by
the number of factors??
It uses the mean of each factor variable. The $means component of
Hello,
I am fitting a coxph model with factors. I am running into problems when
using 'survfit'. I am unsure how R is treating the factors when I fit, say:
DATA-data.frame(time.sec,done,f.pom=factor(f.pom),po,vo)
final-coxph(Surv(time.sec,done)~f.pom*vo+po,data=DATA)
Kylie-Anne Richards kar at itga.com.au writes:
I am fitting a coxph model with factors. I am running into problems when
using 'survfit'. I am unsure how R is treating the factors when I fit, say:
DATA-data.frame(time.sec,done,f.pom=factor(f.pom),po,vo)
