condition mean min max ZT0-3 20.049999999999997 20.049999999999997 20.049999999999997 ZT4-7 6.4 6.4 6.4 ZT8-11 30.85 30.85 30.85 ZT12-15 10.55 10.55 10.55 ZT16-19 9.05 9.05 9.05 ZT20-23 26.35 26.35 26.35