condition mean min max ZT0-3 4.25 4.25 4.25 ZT4-7 1.8 1.8 1.8 ZT8-11 4.7 4.7 4.7 ZT12-15 4.4 4.4 4.4 ZT16-19 6.2 6.2 6.2 ZT20-23 2.75 2.75 2.75