negbin1 {addreg} | R Documentation |
Specifies the information required to fit a negative binomial 1 (NB1) model.
negbin1(link, phi = stop("'phi' must be given"))
link |
included for compatibility with |
phi |
the value of the scale parameter of the NB1 distribution (see
"Details"). This can be set to |
The NB1 distribution can be parameterised in
terms of a mean \mu
and scale parameter \phi
(the
phi
argument of this function), such that if
Y \sim NB1(\mu, \phi)
, then E(Y) = \mu
and
Var(Y) = (1+\phi)\mu
.
These can be related to the size
and prob
arguments
of the NegBinomial
functions by size
= \mu / \phi
and prob
= 1 / (1 + \phi)
.
An object of class "family"
: see family
for
full details. Note that when the estimate of phi
is updated in
a model, this family
object must be reloaded using the new
estimate.
Mark W. Donoghoe markdonoghoe@gmail.com