# anova.DirichletRegModel: Compare Dirichlet Regression Models using an LRT In DirichletReg: Dirichlet Regression in R

## Description

This function allows for pairwise tests of Dirichlet regression models using a likelihood ratio test (LRT).

## Usage

 ```1 2``` ```## S3 method for class 'DirichletRegModel' anova(object, ..., sorted = FALSE) ```

## Arguments

 `object` the model to be compared against those listed in ... `...` models to be tested against the one specified as `object` `sorted` should the models be sorted according to their numbers or parameters?

## Details

The test statistic is computed LR=-2[log(La)-log(Lb)] where Li is the likelihood of model i with df equal to the difference of the number of parameters in the models.

Marco J. Maier

## Examples

 ```1 2 3 4 5 6``` ```ALake <- ArcticLake ALake\$AL <- DR_data(ArcticLake[,1:3]) mod0 <- DirichReg(AL ~ 1, ALake) mod1 <- DirichReg(AL ~ depth, ALake) mod2 <- DirichReg(AL ~ depth + I(depth^2), ALake) anova(mod1, mod0, mod2, sorted = TRUE) ```

### Example output

```Loading required package: Formula
Warning messages:
1: In rgl.init(initValue, onlyNULL) : RGL: unable to open X11 display
2: 'rgl_init' failed, running with rgl.useNULL = TRUE
call: fun(...)
Warning in DR_data(ArcticLake[, 1:3]) :
not all rows sum up to 1 => normalization forced
Analysis of Deviance Table

Model 3: DirichReg(formula = AL ~ depth + I(depth^2), data = ALake)
Model 1: DirichReg(formula = AL ~ depth, data = ALake)
Model 2: DirichReg(formula = AL ~ 1, data = ALake)

Deviance N. par Difference df  Pr(>Chi)
Model 3 -217.994      6
Model 1 -202.739      3     15.254  3  0.001612 **
Model 2  -79.059      9    138.935  3 < 2.2e-16 ***
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
```

DirichletReg documentation built on Jan. 11, 2019, 9:04 a.m.