R: Calculating variance-covariance matrix for objects of class...

vcov.drc {drc} | R Documentation

## Calculating variance-covariance matrix for objects of class 'drc'

### Description

'vcov' returns the estimated variance-covariance matrix for the parameters in the non-linear function.

### Usage

      ## S3 method for class 'drc'
    vcov(object, ..., corr = FALSE, od = FALSE, pool = TRUE, unscaled = FALSE)

### Arguments

`object` | an object of class 'drc'.
`...` | additional arguments.
`corr` | logical. If TRUE a correlation matrix is returned.
`od` | logical. If TRUE adjustment for over-dispersion is used. This argument only makes a difference for binomial data.
`pool` | logical. If TRUE curves are pooled. Otherwise they are not. This argument only works for models with independently fitted curves as specified in `drm`.
`unscaled` | logical. If TRUE the unscaled variance-covariance is returned. This argument only makes a difference for continuous data.

### Value

A matrix of estimated variances and covariances.

### Author(s)

Christian Ritz

### Examples

    ## Fitting a four-parameter log-logistic model
    ryegrass.m1 <- drm(rootl ~ conc, data = ryegrass, fct = LL.4())
    vcov(ryegrass.m1)
    vcov(ryegrass.m1, corr = TRUE)

[Package drc version 3.0-1 Index]