loglik_zip

vector of binary operators. <code>z == 0</code> for observations 
considered belnging to the negative binomial distribution, <code>z == 1</code> 
for observations considered to be 'extra' zeros.

current value for the Poisson likelihood lambda parameter.

vector of 'extra' zero-count probabilities.

Data likelihood fuction for zero-inflated Poisson model 
regression using <code><a rd-options="" href="/link/zero_poisson?package=hurdlr&version=0.1" data-mini-rdoc="hurdlr::zero_poisson">zero_poisson</a></code>.

When considering count data, it is often the case that many more zero counts than would be expected of some given distribution are observed. It is well established that data such as this can be reliably modelled using zero-inflated or hurdle distributions, both of which may be applied using the functions in this package. Bayesian analysis methods are used to best model problematic count data that cannot be fit to any typical distribution. The package functions are flexible and versatile, and can be applied to varying count distributions, parameter estimation with or without explanatory variable information, and are able to allow for multiple hurdles as it is also not uncommon that count data have an abundance of large-number observations which would be considered outliers of the typical distribution. In lieu of throwing out data or misspecifying the typical distribution, these extreme observations can be applied to a second, extreme distribution. With the given functions of this package, such a two-hurdle model may be easily specified in order to best manage data that is both zero-inflated and over-dispersed.

Earvin Balderama

hurdlr

Zero-Inflated and Hurdle Modelling Using Bayesian Inference

Taylor Trippe

loglik_zip function

Data likelihood fuction for zero-inflated Poisson model 
regression using <code><a rd-options='' href='zero_poisson'>zero_poisson</a></code>.

loglik_zip: Zero-inflated Poisson Data Likelihood

Description

Usage

Arguments

Value

See Also