def markedness(self):
return self.precision() + self.npv() - <NUM_LIT:1><EOL>
Return markedness.

        Markedness is defined as :math:`precision + npv - 1`

        Returns
        -------
        float
            The markedness of the confusion table

        Example
        -------
        >>> ct = ConfusionTable(120, 60, 20, 30)
        >>> ct.markedness()
        0.5238095238095237