code: public DoubleMomentStatistics combine(final DoubleMomentStatistics other) {
  		super.combine(other);
  		_min = Math.min(_min, other._min);
  		_max = Math.max(_max, other._max);
  		_sum.add(other._sum);
  
  		return this;
  	}
docs: Combine two {@code DoubleMoments} statistic objects.
  
  @param other the other {@code DoubleMoments} statistics to combine with
  {@code this} one.
  @return {@code this} statistics object
  @throws java.lang.NullPointerException if the other statistical summary
  is {@code null}.