vcov.survstan function

Variance-covariance matrix

This function extracts and returns the variance-covariance matrix associated with the regression coefficients when the maximum likelihood estimation approach is used in the model fitting.

## S3 method for class 'survstan'
vcov(object, all = FALSE, ...)

Arguments

• object: an object of the class survstan.
• all: logical; if FALSE (default), only covariance matrix associated with regression coefficients is returned; if TRUE, the full covariance matrix is returned.
• ...: further arguments passed to or from other methods.

Returns

the variance-covariance matrix associated with the parameters estimators.

Examples

library(survstan)
fit <- aftreg(Surv(futime, fustat) ~ ecog.ps + rx, data = ovarian, baseline = "weibull", init = 0)
vcov(fit)