drc: vcov.drc – R documentation

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drc

vcov.drc

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)

drc

Analysis of Dose-Response Curves

v3.0-1

GPL-2 | file LICENCE

Authors

Christian Ritz <ritz@bioassay.dk>, Jens C. Strebig <streibig@bioassay.dk>

Initial release

2016-08-25