condition mean min max ZT0-3 3.1500000000000004 3.1500000000000004 3.1500000000000004 ZT4-7 3.0 3.0 3.0 ZT8-11 7.3 7.3 7.3 ZT12-15 2.8 2.8 2.8 ZT16-19 4.65 4.65 4.65 ZT20-23 3.25 3.25 3.25