R: Extracting the log likelihood

logLik.drc {drc} | R Documentation

## Extracting the log likelihood

### Description

`loglik` extracts the value of the log likelihood function evaluated at the parameter estimates.

### Usage

      ## S3 method for class 'drc'
    logLik(object, ...)

### Arguments

`object` | an object of class 'drc'.
`...` | additional arguments.

### Value

The evaluated log likelihood as a numeric value and the corresponding degrees of freedom as well as the number of observations as attributes.

### Note

The value of the log likelihood could be used to compare model fits of the same data based on different dose-response models or based on the same model but fitted different algorithms, software programmes, or starting values. For comparisons: Larger is better.

### Author(s)

Christian Ritz

### Examples

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

[Package drc version 3.0-1 Index]