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survreg help in R

2 messages · murphy82nd, David Winsemius

murphy82nd
# 
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:
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.
David Winsemius
# 
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