[R] Weibull survival modeling with covariate

From: <sms13+_at_pitt.edu>
Date: Thu 09 Jun 2005 - 10:39:21 EST


I was wondering if someone familiar
with survival analysis can help me with the following.
I would like to fit a Weibull curve,
that may be dependent on a covariate,
my dataframe "labdata" that has the
fields "cov", "time", and "censor". Do I do the following?
wieb<-survreg(Surv(labdata$time,
labadata$censor)~labdata$cov,
dist="weibull")

This returns:
> weib

Call:
survreg(formula = Surv(labdata$time,
labdata$censor) ~ labdata$cov,

    dist = "weibull")

Coefficients:
(Intercept) labdata$cov
8.091955112 0.001552897

Scale= 0.7532474

Loglik(model)= -12633.6
Loglik(intercept only)= -12734.8

        Chisq= 202.41 on 1 degrees of
freedom, p= 0
n= 5496

I am not quite sure how to use the
output. I see that it gives the Scale
parameter. How do I find the Shape
paramater as a function of the
covariate?

Thank you,
Steven




Steven Shechter
PhD Candidate in Industrial Engineering
University of Pittsburgh
www.pitt.edu/~sms13

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