LR.test.asreml: Likelihood ratio test for two asreml-models.
In digiYozhik/msc_thesis: Functions to support master thesis

Description Usage Arguments Details Value Author(s) Examples

Perform a likelihood ratio test for two asreml-models that have an equal fixed part and a nested random part.

1	LR.test.asreml(model0, model1)

`model0`	An asreml-object, see `asreml`.
`model1`	An asreml-object with the same fixed part as `model0` and a random part that is an extension of the random part of `model0`.

The likelihood ratio test is performed by comparing two times the difference in log-likelihood with the quantiles if the χ^2-distribution with as degrees of freedom the difference in number of variance components estimated in both models.

If the degrees of freedom equal 1, the obtained p-value is divided by 2.

A list with class "htest" containing the following components:

statistic: The value of the test statistic.
parameter: The degrees of freedom for the test statistic.
p.value: The p-value for the test.
conf.int: NULL
estimate: NULL
null.value: NULL
alternative: Extended model outperforms the 'null model'.
method: Likelihood ratio test (Chi-square)
data.name: Names of the two models that were tested.

Ruud Derijcker, Katrien Baert

library(asreml)
data(oats)
model0 <- asreml(fixed = yield ~ Variety*Nitrogen, random = ~ Blocks:Wplots,
          data = oats)
model1 <- asreml(fixed = yield ~ Variety*Nitrogen, random = ~ Blocks/Wplots,
          data = oats)
LR.test.asreml(model0, model1)