how to obtain CI of the random effects variance in a frailty model?

Hello,

 

Does anyone know how to obtain a confidence interval for the random effects variance  in a frailty Proporcional Hazard Cox (PHC) model?. 

 

The sintaxis in R is of the form:

model<-coxph(Surv(time,cens)~frailty.gaussian(hospital))

from the 'survival' library.

 

If I'm not wrong, the instruction

summary(model)

returns the estimation of the random effects (hospital) variance, but not the deviation of this estimation.

 

Or, if there's another function instead, perhaps from another library, of 'coxph' that could estimate a frailty PHC model and the standard deviation of the random effects variance.

 

 

Thanks in advance.