def pr_amean(self):
return amean((self.precision(), self.recall()))<EOL>
r"""Return arithmetic mean of precision & recall.

        The arithmetic mean of precision and recall is defined as:
        :math:`\frac{precision \cdot recall}{2}`

        Cf. https://en.wikipedia.org/wiki/Arithmetic_mean

        Returns
        -------
        float
            The arithmetic mean of the confusion table's precision & recall

        Example
        -------
        >>> ct = ConfusionTable(120, 60, 20, 30)
        >>> ct.pr_amean()
        0.8285714285714285