Regression Analysis with R

Count data model

Poisson regression is a form of regression used to model the count of data in contingency tables. For example, counting the number of births or the number of wins in a series of soccer matches. Poisson regression assumes that the response variable Y has a Poisson distribution, and that the logarithm of its expected value can be modelled by a linear combination of unknown parameters. Poisson regression is sometimes also known as a log-linear model, especially when it is used to model contingency tables.