condition mean min max ZT0-3 20.799999999999997 20.799999999999997 20.799999999999997 ZT4-7 27.6 27.6 27.6 ZT8-11 7.3500000000000005 7.3500000000000005 7.3500000000000005 ZT12-15 22.5 22.5 22.5 ZT16-19 17.85 17.85 17.85 ZT20-23 25.599999999999998 25.599999999999998 25.599999999999998