[R] Use of survreg.distributions
Terry Therneau
therneau at mayo.edu
Fri Apr 25 14:46:45 CEST 2008
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I am using survreg(Surv()) for fitting a Tobit model of left-censored
longitudinal data. For logarithmic transformation of y data, I am trying use
survreg.distributions in the following way:
tfit=survreg(Surv(y, y>=-5, type="left")~x + cluster(id), dist="gaussian",
data=y.data, scale=0, weights=w)
my.gaussian<-survreg.distributions$gaussian
my.gaussian$name="lognormal"
my.gaussian$dist<-my.gaussian
tfit=survreg(Surv(y, y>=-5, type="left")~x + cluster(id), dist=my.gaussian,
data=y.data, scale=0, weights=w)
If I run these codes then I got the following error message,
Error in survreg(Surv(y, y >= -5, type = "left") ~ x + :
Invalid distribution object
Does anybody can help me in identifying the error(s) in these code please?
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Can you tell us what you are trying to do?
Your first model was a fit of y ~ x + eps, eps ~ Gaussian. If what you want
is log(y) ~ x + eps, then all that you need do is use dist="loggaussian" in the
survreg call. (Or 'lognormal'; which is the same distribution.)
Terry Therneau
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