'Parameters
dim : int
Dimension of the scale matrix
%(_doc_default_callparams)s
Notes
As this function does no argument checking, it should not be
called directly; use \'mean\' instead.'

def _mean(self, dim, df, scale):

    if (df > (dim + 1)):
        out = (scale / ((df - dim) - 1))
    else:
        out = None
    return out
