# statsmodels.genmod.families.family.Poisson.loglike_obs¶

Poisson.loglike_obs(endog, mu, var_weights=1.0, scale=1.0)[source]

The log-likelihood function for each observation in terms of the fitted mean response for the Poisson distribution.

Parameters: endog (array) – Usually the endogenous response variable. mu (array) – Usually but not always the fitted mean response variable. var_weights (array-like) – 1d array of variance (analytic) weights. The default is 1. scale (float) – The scale parameter. The default is 1. ll_i – The value of the loglikelihood evaluated at (endog, mu, var_weights, scale) as defined below. float

Notes

$ll_i = var\_weights_i / scale * (endog_i * \ln(\mu_i) - \mu_i - \ln \Gamma(endog_i + 1))$