condition mean min max ZT0-3 2.35 2.35 2.35 ZT4-7 2.8 2.8 2.8 ZT8-11 7.5 7.5 7.5 ZT12-15 3.3 3.3 3.3 ZT16-19 3.5500000000000003 3.5500000000000003 3.5500000000000003 ZT20-23 2.5 2.5 2.5