condition mean min max ZT0-3 1.6463383333333332 1.3404699999999998 1.953665 ZT4-7 1.7521749999999998 1.7521749999999998 1.7521749999999998 ZT8-11 2.2102399999999998 2.2102399999999998 2.2102399999999998 ZT12-15 3.2274849999999997 2.912985 3.541985 ZT16-19 3.01762 3.01762 3.01762 ZT20-23 2.701425 2.701425 2.701425