condition mean min max ZT0-3 4.1 4.1 4.1 ZT4-7 3.8 3.8 3.8 ZT8-11 1.35 1.35 1.35 ZT12-15 3.0999999999999996 3.0999999999999996 3.0999999999999996 ZT16-19 1.55 1.55 1.55 ZT20-23 1.7 1.7 1.7