lrtest {epicalc}R Documentation

Likelihood ratio test

Description

Likelihood ratio test for 'glm'

Usage

lrtest (model1, model2)

Arguments

model1, model2 Two models having the set of same records and the same type ('family' and 'link') of modelling.

Details

Likelihood ratio test checks the difference between -2*logLikelihood of the two models against the change in degrees of freedom using a chi-squared test. It is best applied to a model from 'glm' to test the effect of a factor with more than two levels. The records used in the dataset for both models MUST be the same.

Author(s)

Virasakdi Chongsuvivatwong <cvirasak@medicine.psu.ac.th>

See Also

'glm', 'logLik', 'deviance'

Examples

model0 <- glm(case ~ induced + spontaneous, family=binomial, data=infert)
model1 <- glm(case ~ induced, family=binomial, data=infert)
lrtest (model0, model1)
lrtest (model1, model0) # same answer

[Package epicalc version 2.5.0.3 Index]