[R] p-value=0 running log-rank test

[Anne Karin da Mota Borges]

Dear all,

I have a question concerning the p-value. When running log-rank test I get
a p-value = 0.
What is it mean? Can this be true? Why aren´t there decimal points? Is
there a way to find out the exact p-value?

Here is the output:

> survdiff(Surv(tempo2,status)~tphist, data=base,rho=0)
Call:
survdiff(formula = Surv(tempo2, status) ~ tphist, data = base,
    rho = 0)

           N Observed Expected (O-E)^2/E (O-E)^2/V
tphist=1 513       19   40.879    11.710  9.00e+01
tphist=2  49        4    3.892     0.003  3.27e-03
tphist=3  23        9    1.686    31.717  3.29e+01
tphist=4  18       15    0.543   385.172  3.91e+02

 Chisq= 430  on 3 degrees of freedom, p= 0

Thank you in advance.

Anne.

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