condition mean min max ZT0-3 2.85 2.85 2.85 ZT4-7 2.9 2.9 2.9 ZT8-11 3.5 3.5 3.5 ZT12-15 17.4 17.4 17.4 ZT16-19 26.799999999999997 26.799999999999997 26.799999999999997 ZT20-23 26.599999999999998 26.599999999999998 26.599999999999998