condition mean min max ZT0-3 2.7 2.7 2.7 ZT4-7 1.8 1.8 1.8 ZT8-11 24.5 24.5 24.5 ZT12-15 6.85 6.85 6.85 ZT16-19 3.9000000000000004 3.9000000000000004 3.9000000000000004 ZT20-23 4.3 4.3 4.3