code: public static OnLineStatistics add(OnLineStatistics A, OnLineStatistics B)
     {
         OnLineStatistics toRet = A.clone();
         toRet.add(B);
         return toRet;
     }
docs: Computes a new set of counts that is the sum of the counts from the given distributions.
  <br><br>
  NOTE: Adding two statistics is not as numerically stable. If A and B have values of similar
  size and scale, the values of the 3rd and 4th moments {@link #getSkewness() } and
  {@link #getKurtosis() } will suffer from catastrophic cancellations, and may not
  be as accurate.
  @param A the first set of statistics
  @param B the second set of statistics
  @return a new set of statistics that is the addition of the two.