A vcov method for nonprobsvy class.
Usage
# S3 method for class 'nonprobsvy'
vcov(object, ...)
Arguments
- object
object of nonprobsvy class.
- ...
additional arguments for method functions
Value
A covariance matrix for fitted coefficients
Details
Returns a estimated covariance matrix for model coefficients
calculated from analytic hessian or Fisher information matrix usually
utilising asymptotic effectiveness of maximum likelihood estimates.