condition mean min max ZT0-3 3.5 3.5 3.5 ZT4-7 2.4 2.4 2.4 ZT8-11 8.8 8.8 8.8 ZT12-15 3.3 3.3 3.3 ZT16-19 5.05 5.05 5.05 ZT20-23 4.8 4.8 4.8