condition mean min max ZT0-3 8.605562 8.605562 8.605562 ZT4-7 8.9150785 8.9150785 8.9150785 ZT8-11 8.768714 8.768714 8.768714 ZT12-15 8.6329 8.6329 8.6329 ZT16-19 10.252222499999998 10.252222499999998 10.252222499999998 ZT20-23 10.109457 10.109457 10.109457