condition mean min max ZT0-3 5.6674066666666665 3.26854 7.57967 ZT4-7 3.2945450000000003 3.2945450000000003 3.2945450000000003 ZT8-11 2.9146549999999998 2.9146549999999998 2.9146549999999998 ZT12-15 3.3254574999999997 3.1628 3.4881149999999996 ZT16-19 4.934235 4.934235 4.934235 ZT20-23 7.767785 7.767785 7.767785