condition mean min max ZT0-3 2.05 2.05 2.05 ZT4-7 1.1 1.1 1.1 ZT8-11 3.25 3.25 3.25 ZT12-15 3.9 3.9 3.9 ZT16-19 4.0 4.0 4.0 ZT20-23 1.3 1.3 1.3