This example analyzes the data from Beitler and Landis (1985), which represent results from a multi-center clinical trial investigating the effectiveness of two topical cream treatments (active drug, ...

The negative binomial distribution contains a parameter k, called the negative binomial dispersion parameter. This is not the same as the generalized linear model dispersion , but it is an additional ...

and of the estimating algorithms used to model count data. The book then gives an in-depth analysis of Poisson regression and an evaluation of the meaning and nature of overdispersion, followed by a ...