condition mean min max ZT0-3 3.7 3.7 3.7 ZT4-7 4.3 4.3 4.3 ZT8-11 6.2 6.2 6.2 ZT12-15 7.85 7.85 7.85 ZT16-19 4.25 4.25 4.25 ZT20-23 3.5500000000000003 3.5500000000000003 3.5500000000000003