[R] survreg with numerical covariates

[Ales Ziberna]

As you can se from the example bellow, survreg works prefeclty fine with 
numerical values. (I'm runing R2.0.1 on WinXP(SP2) and 32bit AMD with 
survival version 2.17.).

As the posting guide asks, plese provide a small example.

Ales Ziberna


> library(survival)
Loading required package: splines
> data(cancer)
> survreg(Surv(time, status)~age,data=cancer)
Call:
survreg(formula = Surv(time, status) ~ age, data = cancer)

Coefficients:
(Intercept)         age
 6.88712062 -0.01360829

Scale= 0.7587515

Loglik(model)= -1151.9   Loglik(intercept only)= -1153.9
        Chisq= 3.91 on 1 degrees of freedom, p= 0.048
n= 228

----- Original Message ----- 
From: "Richard Mott" <Richard.Mott at well.ox.ac.uk>
To: <r-help at stat.math.ethz.ch>
Sent: Tuesday, April 26, 2005 11:32 PM
Subject: [R] survreg with numerical covariates


> Does anyone know if the survreg function in the survival package can fit 
> numerical covariates ?
>
> When I fit a survival model of the form
>
> survreg( Surv(time,censored) ~ x )
>
> then x is always treated as a factor even if it is numeric (and even if I 
> try to force it to be numeric using as.numeric(x). Thus, in the particular 
> example I am analysing, a simple numerical covariate becomes a factor with 
> 190 levels. Is this the expected behaviour ? Am I doing something wrong ?
>
> I am running R 2.0.1 on a 64bit Debian Linux system, and version 2.17 of 
> the survival package
>
>
> Thanks
>
> Richard Mott
>
> -- 
> ----------------------------------------------------
> Richard Mott       | Wellcome Trust Centre
> tel 01865 287588   | for Human Genetics
> fax 01865 287697   | Roosevelt Drive, Oxford OX3 7BN
>
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