Quenouille (1949), Tukey (1958): the n leave-one-out values, bias
(n-1)(mean(loo) - estimate) and variance
(n-1)/n * sum((loo - mean(loo))^2). The (n-1) factors ARE the
estimator – the leave-one-out values huddle n-1 times closer than
independent replicates, and the inflation undoes exactly that; for
the mean the jackknife variance equals s^2/n EXACTLY. Inconsistent
for non-smooth statistics (the median is the canonical failure,
Efron 1979 Sec. 3), and the output says so.
