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Family Objects for Models

Syntax

family(object)
binomial(link=logit)
gaussian()
Gamma(link=inverse)
inverse.gaussian()
poisson(link=log)
quasi(link=identity, variance=constant)

Arguments

link 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 other families have only a single permissible link function. 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 family.
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).

Description

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.

References

McCullagh P. and J. A. Nelder (1989). Generalized Linear 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.

See Also

glm, power.