[R] survreg help in R
David Winsemius
dwinsemius at comcast.net
Sun Mar 8 19:25:09 CET 2009
I think R and survival took a look at what you provided for a formula
to survreg and rejected it because it had no lh-rh separator, "~", and
thus no rh terms. Turns out that it also expects a dataframe even if
both terms for the Surv function are already given and there is
nothing further to be evaluated. Try adding:
> dft <- data.frame(times=times, censor=censor)
> survreg(Surv(times,censor) ~ , dist='weibull', data=dft)
Error: syntax error
> survreg(Surv(times,censor) ~ ., dist='weibull', data=dft)
Call:
survreg(formula = Surv(times, censor) ~ ., data = dft, dist = "weibull")
Coefficients:
(Intercept)
4.591518
Scale= 0.5965153
Loglik(model)= -50.4 Loglik(intercept only)= -50.4
n= 18
--
On Mar 8, 2009, at 1:34 PM, murphy82nd wrote:
>
> Hey all,
> I am trying to use the survreg function in R to estimate the mean and
> standard deviation to come up with the MLE of alpha and lambda for the
> weibull distribution. I am doing the following:
> times<-c(10,13,18,19,23,30,36,38,54,56,59,75,93,97,104,107,107,107)
> censor<-c(1,0,0,1,0,1,1,0,0,0,1,1,1,1,0,1,0,0)
> survreg(Surv(times,censor),dist='weibull')
> and I get the following error:
>> survreg(Surv(times,censor),dist='weibull')
> Error in x$terms : $ operator is invalid for atomic vectors
>
> I am fairly new to R and don't understand what I am doing wrong.
> Any help
> would be great.
> --
> View this message in context: http://www.nabble.com/survreg-help-in-R-tp22400405p22400405.html
> Sent from the R help mailing list archive at Nabble.com.
>
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
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