Checking for overdispersion
In this exercise you will check for overdispersion in the model you fitted previously, namely the horseshoe crab Poisson model where you fitted sat given width. Recall from the video that to check for potential overdispersion in the fit you would compute the following
model.pearson_chi2 / model.df_resid
where .pearson_chi2 represents Pearson statistic and .df_resid represents the degrees of freedom of the residuals.
The model crab_pois and crab dataset are preloaded in the workspace.
Cet exercice fait partie du cours
Generalized Linear Models in Python
Instructions
- Compute the ratio of the Pearson statistic and the degrees of freedom of the residuals for the
crab_poisPoisson regression model.
Exercice interactif pratique
Essayez cet exercice en complétant cet exemple de code.
# Compute and print the overdispersion approximation
____(____.____ / ____.____)