condition mean min max ZT0-3 2.9495924999999996 2.163795 3.7353899999999998 ZT4-7 5.07595 5.07595 5.07595 ZT8-11 11.9967 11.9967 11.9967 ZT12-15 15.492266666666666 14.128733333333335 16.8558 ZT16-19 10.8689 10.8689 10.8689 ZT20-23 6.69745 6.69745 6.69745