* averaged shortfallness, defined as
* {@latex[ \mathrm{E}\left[ t-x \;|\; x<t \right] }
*/
public /*@Real*/ double averageShortfall(final /*@Real*/ double target) /*@ReadOnly*/ {
final Ops.DoubleOp minus = new Bind1st(target, new Minus());
final Ops.DoublePredicate less = new Bind1stPredicate(target, new LessThanPredicate());
final Pair<Double, Integer> result = expectationValue(minus, less);
final double x = result.first();
final Integer N = result.second();