vcov.drc: Calculating variance-covariance matrix for objects of class...

In drc: Analysis of Dose-Response Curves

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 documentation built on May 1, 2019, 8:43 p.m.