ZIM

Analyze count time series with excess zeros. Two types of statistical models are supported: Markov regression by Yang et al. (2013) doi:10.1016/j.stamet.2013.02.001 and state-space models by Yang et al. (2015) doi:10.1177/1471082X14535530. They are also known as observation-driven and parameter-driven models respectively in the time series literature. The functions used for Markov regression or observation-driven models can also be used to fit ordinary regression models with independent data under the zero-inflated Poisson (ZIP) or zero-inflated negative binomial (ZINB) assumption. Besides, the package contains some miscellaneous functions to compute density, distribution, quantile, and generate random numbers from ZIP and ZINB distributions.