family(object) binomial(link = "logit") gaussian(link ="identity") Gamma(link = "inverse") inverse.gaussian(link = "1/mu^2") poisson(link = "log") quasi(link = "identity", variance = "constant") print.family(x, ...)
link
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a specification for the model link function.
The binomial family admits the links logit,
probit and cloglog (complementary log-log);
the Gamma family the links identity,
inverse and log,
the poisson family the links identity
log and sqrt, and
the quasi family the links logit, probit,
cloglog, identity, inverse, log,
1/mu^2 and sqrt.
The function power can also be used to create a
power link function for the quasi family.
The other families have only one permissible link function:
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variance
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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.
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object
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the function family accesses the family
objects which are stored within objects created by modelling
functions (e.g. glm).
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glm. See the
documentation for glm for the details on how such model
fitting takes place.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.
glm, power.nf <- gaussian()# Normal family nf str(nf)# internal STRucture gf <- Gamma() gf str(gf) gf$linkinv all(1:10 == gf$linkfun(gf$linkinv(1:10)))# is TRUE gf$variance(-3:4) #- == (.)^2