code: public static OnLineStatistics remove(OnLineStatistics A, OnLineStatistics B)
     {
         OnLineStatistics toRet = A.clone();
         toRet.remove(B);
         return toRet;
     }
docs: Computes a new set of statistics that is the equivalent of having removed
  all observations in {@code B} from {@code A}. <br>
  NOTE: removing statistics is not as numerically stable. The values of the
  3rd and 4th moments {@link #getSkewness() } and {@link #getKurtosis() }
  will be inaccurate for many inputs. The {@link #getMin() min} and
  {@link #getMax() max}  can not be determined in this setting, and will not
  be altered.
  @param A the first set of statistics, which must have a larger value for
  {@link #getSumOfWeights() } than {@code B}
  @param B the set of statistics to remove from {@code A}.
  @return a new set of statistics that is the removal of {@code B} from
  {@code A}