dzagamma2: Zero-augmented gamma probability density

In rmcelreath/rethinking: Statistical Rethinking book package

Zero-augmented gamma probability density

Description

Function for computing density from a zero-augmented gamma probability distribution.

Usage

dzagamma2( x , prob , mu , scale , log=FALSE )

Arguments

x	Values to compute densities for
prob	Probability of a zero
mu	Mean of gamma distribution
scale	Scale parameter (same as scale in dgamma)
log	If TRUE, returns log-density instead of density

Details

This distribution is defined as a finite mixture of zeros and strictly positive gamma distributed values, where prob determines the weight of the zeros. As such, the probability of a zero is prob, and the probability of a non-zero value x is (1-prob)*dgamma( x , mu/scale , scale ).

Author(s)

Richard McElreath

rmcelreath/rethinking documentation built on Aug. 26, 2024, 5:54 p.m.