'Generalized residuals
Notes
The generalized residuals for the Probit model are defined
.. math:: y\frac{\phi(X\beta)}{\Phi(X\beta)}-(1-y)\frac{\phi(X\beta)}{1-\Phi(X\beta)}'

@cache_readonly
def resid_generalized(self):

    model = self.model
    endog = model.endog
    XB = self.predict(linear=True)
    pdf = model.pdf(XB)
    cdf = model.cdf(XB)
    return (((endog * pdf) / cdf) - (((1 - endog) * pdf) / (1 - cdf)))
