condition mean min max ZT0-3 2.3499999999999996 2.3499999999999996 2.3499999999999996 ZT4-7 1.2 1.2 1.2 ZT8-11 15.95 15.95 15.95 ZT12-15 8.5 8.5 8.5 ZT16-19 14.4 14.4 14.4 ZT20-23 14.3 14.3 14.3