Covariance of the regression coefficients

Usage

# S3 method for zibellreg
vcov(object, ...)

Arguments

object: an object of the class bellreg
...: further arguments passed to or from other methods.

Value

the variance-covariance matrix associated with the regression coefficients.

Examples

# \donttest{
data(cells)
fit <- zibellreg(cells ~ smoker + gender|smoker + gender, data = cells)
vcov(fit)
#>             (Intercept)      smoker      gender (Intercept)      smoker
#> (Intercept)  0.71375095 -0.66593937 -0.16291334  0.08674953 -0.06934253
#> smoker      -0.66593937  0.67741383  0.11224115 -0.07505623  0.07900509
#> gender      -0.16291334  0.11224115  0.17691041 -0.03594104  0.02388996
#> (Intercept)  0.08674953 -0.07505623 -0.03594104  0.03234666 -0.02221435
#> smoker      -0.06934253  0.07900509  0.02388996 -0.02221435  0.03363681
#> gender      -0.05316462  0.03930472  0.04234357 -0.02586122  0.01346487
#>                  gender
#> (Intercept) -0.05316462
#> smoker       0.03930472
#> gender       0.04234357
#> (Intercept) -0.02586122
#> smoker       0.01346487
#> gender       0.03149926
# }