Extract model parameters and their covariance matrix as well as degrees of freedom (if available) from a fitted model.

`modelparm(model, coef., vcov., df, ...)`

coef.

an accessor function for the model parameters. Alternatively, the vector of coefficients.

vcov.

an accessor function for the covariance matrix of the model parameters. Alternatively, the covariance matrix directly.

df

an optional specification of the degrees of freedom to be used in subsequent computations.

…

additional arguments, currently ignored.

An object of class `modelparm`

with elements

model parameters

covariance matrix of model parameters

degrees of freedom

One can't expect `coef`

and `vcov`

methods
for arbitrary models to
return a vector of \(p\) fixed effects model parameters (`coef`

)
and corresponding \(p \times p\) covariance matrix (`vcov`

).

The `coef.`

and `vcov.`

arguments can be used to define
modified `coef`

or `vcov`

methods for a specific model.
Methods for `lmer`

and `survreg`

objects are available (internally).

For objects inheriting from class `lm`

the degrees of
freedom are determined from `model`

and the corresponding
multivariate t distribution is used by all methods to `glht`

objects. By default, the asymptotic multivariate normal distribution
is used in all other cases unless `df`

is specified by the user.