anova.negbin {MASS}  R Documentation 
Method function to perform sequential likelihood ratio tests for Negative Binomial generalized linear models.
## S3 method for class 'negbin': anova(object, ..., test = "Chisq")
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.

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.
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 reestimated for each
model.
Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.
glm.nb
, negative.binomial
, summary.negbin
m1 < glm.nb(Days ~ Eth*Age*Lrn*Sex, quine, link = log) m2 < update(m1, . ~ .  Eth:Age:Lrn:Sex) anova(m2, m1) anova(m2)