condition mean min max ZT0-3 4.733178333333333 1.73061 6.591934999999999 ZT4-7 2.1764 2.1764 2.1764 ZT8-11 1.5373 1.5373 1.5373 ZT12-15 2.9159474999999997 2.32327 3.508625 ZT16-19 4.545415 4.545415 4.545415 ZT20-23 7.813855 7.813855 7.813855