condition mean min max ZT0-3 3.35 3.35 3.35 ZT4-7 2.5 2.5 2.5 ZT8-11 12.75 12.75 12.75 ZT12-15 3.1500000000000004 3.1500000000000004 3.1500000000000004 ZT16-19 4.1 4.1 4.1 ZT20-23 3.6500000000000004 3.6500000000000004 3.6500000000000004