condition mean min max ZT0-3 1.55 1.55 1.55 ZT4-7 2.8 2.8 2.8 ZT8-11 2.95 2.95 2.95 ZT12-15 2.6999999999999997 2.6999999999999997 2.6999999999999997 ZT16-19 3.75 3.75 3.75 ZT20-23 14.9 14.9 14.9