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FFaammiillyy OObbjjeeccttss ffoorr MMooddeellss
family(object)
binomial(link=logit)
gaussian()
Gamma(link=inverse)
inverse.gaussian()
poisson(link=log)
quasi(link=identity, variance=constant)
AArrgguummeennttss::
link: a specification for the model link function. The
`binomial' family admits the links; `logit', `pro-
bit' and `cloglog' (complementary log-log), the
`Gamma' family the links; `identity', `inverse'
and `log', the `poisson' family the links; `iden-
tity' `log' and `sqrt', and the `quasi' family the
links; `logit', `probit', `cloglog', `identity',
`inverse', `log', `1/mu^2' and `sqrt'. The other
families have only a single permissible link func-
tion. These are the `identity' for the `gaussian'
family and `1/mu^2' for the `inverse.gaussian'
family. The function `power' can also be used to
create a power link function for the `quasi' fam-
ily.
variance: for all families, other than `quasi', the variance
function is determined by the family. The `quasi'
family will accept the specifications `constant',
`mu(1-mu)', `mu', `mu^2' and `mu^3' as variance
function.
object: the function `family' accesses the `family'
objects which are stored within objects created by
modelling functions (e.g. `glm').
DDeessccrriippttiioonn::
Family objects provide a convenient way to specify the
details of the models used by functions such as `glm'.
See the documentation for `glm' for the details on how
such model fitting takes place.
RReeffeerreenncceess::
McCullagh P. and J. A. Nelder (1989). Generalized Lin-
ear Models. London: Chapman and Hall.
Dobson, A. J. (1983). An Introduction to Statistical
Modelling. London: Chapman and Hall.
Cox, D. R. and E. J. Snell (1981). Applied Statistics;
Principles and Examples. London: Chapman and Hall.
SSeeee AAllssoo::
`glm', `power'.
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