# anova.negbin

##### Likelihood Ratio Tests for Negative Binomial GLMs

Method function to perform sequential likelihood ratio tests for Negative Binomial generalized linear models.

- Keywords
- regression

##### Usage

```
# S3 method for negbin
anova(object, …, test = "Chisq")
```

##### Arguments

- object
Fitted model object of class

`"negbin"`

, inheriting from classes`"glm"`

and`"lm"`

, specifying a Negative Binomial fitted GLM. Typically the output of`glm.nb()`

.- …
Zero or more additional fitted model objects of class

`"negbin"`

. They should form a nested sequence of models, but need not be specified in any particular order.- test
Argument to match the

`test`

argument of`anova.glm`

. Ignored (with a warning if changed) if a sequence of two or more Negative Binomial fitted model objects is specified, but possibly used if only one object is specified.

##### Details

This function is a method for the generic function
`anova()`

for class `"negbin"`

.
It can be invoked by calling `anova(x)`

for an
object `x`

of the appropriate class, or directly by
calling `anova.negbin(x)`

regardless of the
class of the object.

##### Note

If only one fitted model object is specified, a sequential analysis of
deviance table is given for the fitted model. The `theta`

parameter is kept
fixed. If more than one fitted model object is specified they must all be
of class `"negbin"`

and likelihood ratio tests are done of each model within
the next. In this case `theta`

is assumed to have been re-estimated for each
model.

##### References

Venables, W. N. and Ripley, B. D. (2002)
*Modern Applied Statistics with S.* Fourth edition. Springer.

##### See Also

##### Examples

```
# NOT RUN {
m1 <- glm.nb(Days ~ Eth*Age*Lrn*Sex, quine, link = log)
m2 <- update(m1, . ~ . - Eth:Age:Lrn:Sex)
anova(m2, m1)
anova(m2)
# }
```

*Documentation reproduced from package MASS, version 7.3-51.1, License: GPL-2 | GPL-3*