I'm doing survival analysis with interval-cesored data and I'm using intcox() function from the intcox package in R, which is based on the coxph function.
The function returns the output without likelihood ratio test values:
> intcox(surv~sexo,data=dados)
Call:
intcox(formula = surv ~ sexo, data = dados)
coef exp(coef) se(coef) z p
sexojuvenil 2.596 13.4 NA NA NA
sexomacho -0.105 0.9 NA NA NA
Likelihood ratio test=NA on 2 df, p=NA n= 156
I don't know why this is happening... Here is the application of the coxph() function to the same data:
> coxph(Surv(dias_seg,status)~sexo,data=dados)
Call:
coxph(formula = Surv(dias_seg, status) ~ sexo, data = dados)
coef exp(coef) se(coef) z p
sexojuvenil 2.320 10.172 0.630 3.684 0.00023
sexomacho -0.169 0.844 0.252 -0.671 0.50000
Likelihood ratio test=9.28 on 2 df, p=0.00967 n= 156, number of events= 77
str(dados$sexo)
Factor w/ 3 levels "femea","juvenil",..: 3 3 3 3 3 3 3 3 3 3 ...
Can you help me to solve this problem?
Thanks in advance.