stats
OLSInfluence.
resid_var
(cached attribute) estimate of variance of the residuals
sigma2 = sigma2_OLS * (1 - hii)
where hii is the diagonal of the hat matrix
statsmodels.stats.outliers_influence.OLSInfluence.resid_studentized_internal
statsmodels.stats.outliers_influence.OLSInfluence.sigma2_not_obsi