beta.binomial: Beta-Binomial Prior Distribution for Models
Description
Creates an object representing the prior distribution on
models for BAS.
Usage
beta.binomial(alpha=1.0, beta=1.0)
Arguments
alpha
parameter in the beta prior distribution
beta
parameter in the beta prior distribution
Value
returns an object of class "prior", with the family and
hyerparameters.
Details
The beta-binomial distribution on model size is obtained by
assigning each variable inclusion indicator independent Bernoulli
distributions with probability w, and then giving w a beta(alpha,beta)
distribution. Marginalizing over w leads to the distribution on model
size having the beta-binomial distribution. The default hyperparaeters
lead to a uniform distribution over model size.