statsmodels.genmod.families.family.InverseGaussian.loglike_obs¶
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InverseGaussian.
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 Inverse Gaussian distribution.
Parameters: Returns: ll_i – The value of the loglikelihood evaluated at (endog, mu, var_weights, scale) as defined below.
Return type: Notes
\[ll_i = -1/2 * (var\_weights_i * (endog_i - \mu_i)^2 / (scale * endog_i * \mu_i^2) + \ln(scale * \endog_i^3 / var\_weights_i) - \ln(2 * \pi))\]