condition mean min max ZT0-3 20.9 20.9 20.9 ZT4-7 1.4 1.4 1.4 ZT8-11 17.85 17.85 17.85 ZT12-15 7.95 7.95 7.95 ZT16-19 22.35 22.35 22.35 ZT20-23 3.9499999999999997 3.9499999999999997 3.9499999999999997