condition mean min max ZT0-3 4.2 4.2 4.2 ZT4-7 1.4 1.4 1.4 ZT8-11 1.85 1.85 1.85 ZT12-15 2.3 2.3 2.3 ZT16-19 1.9 1.9 1.9 ZT20-23 3.9000000000000004 3.9000000000000004 3.9000000000000004