statsmodels.genmod.families.links.InversePower.inverse_deriv¶ InversePower.inverse_deriv(z)¶ Derivative of the inverse of the power transform Parameters:¶ z : array_like¶z is usually the linear predictor for a GLM or GEE model. Returns:¶ g^(-1)’(z) (ndarray) – The value of the derivative of the inverse of the power transform function