[R] Boot package

Jingky Lozano jlozano at apoy.upm.edu.ph
Wed Apr 21 13:13:14 CEST 2004

Dear mailing list,

I tried to run the example for the conditional bootstap written in the help file
of censboot.  I got the following result:


censboot(data = aml, statistic = aml.fun, R = 499, F.surv = aml.s1, 
    G.surv = aml.s2, strata = aml$group, sim = "cond")

Bootstrap Statistics :
    original    bias    std. error
t1*       31       Inf         NaN
t2*       23 -2.058116    8.670602

I don't know if there is something in the given code that results in "Inf" and
"NaN" result.  I tried a different data, analyzing it without stratification. 
I got a different error:

> data.s1 <- survfit(Surv(time,cens), data=dataset)
> data.s2 <- survfit(Surv(time-0.001*cens,1-cens), data=dataset)
> msurv.cond  <- censboot(data=dataset,statistic=data.fun,R=r,
Error in sample(length(x), size, replace, prob) : 
        invalid first argument

Can the boot package also output standard error and bias of the regression
coefficients if I do a cox proportional hazard analysis applying all the
different bootstrap methods for censored data??? I did a trial and error with
my codes but it all got muddled in the end giving me nothing.  

I hope you can help me with some of my questions. Thank you for your time.



University of the Philippines Manila (http://mail.upm.edu.ph)

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