statsmodels.genmod.families.links.InversePower.inverse_deriv2¶ InversePower.inverse_deriv2(z)¶ Second derivative of the inverse of the power transform Parameters:¶ zarray_likez is usually the linear predictor for a GLM or GEE model. Returns:¶ g^(-1)’(z)ndarrayThe value of the derivative of the inverse of the power transform function