dmicobin: Density function of micobin (mixture of continuous binomial) distribution
Description
Micobin distribution with natural parameter \(\theta\) and dispersion \(psi\), denoted as \(micobin(\theta, \psi)\), is defined as a dispersion mixture of cobin:
$$
Y \sim micobin(\theta, \psi) \iff Y | \lambda \sim cobin(\theta, \lambda^{-1}), (\lambda-1) \sim negbin(2, \psi)
$$
so that micobin density is a weighted sum of cobin density with negative binomial weights.