condition mean min max ZT0-3 16.601695 16.601695 16.601695 ZT4-7 17.824807 17.824807 17.824807 ZT8-11 16.299846 16.299846 16.299846 ZT12-15 17.827627999999997 17.827627999999997 17.827627999999997 ZT16-19 21.487062 21.487062 21.487062 ZT20-23 20.8940735 20.8940735 20.8940735