tr.poisson: Truncated Poisson Prior Distribution for Models
Description
Creates an object representing the prior distribution on
models for BAS using a truncated Poisson Distribution on the
Model Size
Usage
tr.poisson(lambda, trunc)
Arguments
lambda
parameter in the Poisson distribution
representing expected model size with infinite predictors
trunc
parameter that determines truncation in the distribution
i.e. P(M; lambda, trunc) = 0 if M > trunc
Value
hyerparameters.
Details
The Poisson prior distribution on model size is obtained by
assigning each variable inclusion indicator independent Bernoulli
distributions with probability w, and then taking a limit as p goes to
infinity and w goes to zero, such that p*w converges to lambda. The Truncated
version assigns zero probability to all models of size M > trunc.