condition mean min max ZT0-3 3.05 3.05 3.05 ZT4-7 3.9 3.9 3.9 ZT8-11 3.55 3.55 3.55 ZT12-15 10.35 10.35 10.35 ZT16-19 7.8999999999999995 7.8999999999999995 7.8999999999999995 ZT20-23 9.05 9.05 9.05