condition mean min max ZT0-3 17.4 17.4 17.4 ZT4-7 1.7 1.7 1.7 ZT8-11 3.1 3.1 3.1 ZT12-15 3.45 3.45 3.45 ZT16-19 22.549999999999997 22.549999999999997 22.549999999999997 ZT20-23 4.9 4.9 4.9