condition mean min max ZT0-3 7.0 7.0 7.0 ZT4-7 0.6 0.6 0.6 ZT8-11 3.0 3.0 3.0 ZT12-15 5.3 5.3 5.3 ZT16-19 0.9 0.9 0.9 ZT20-23 5.8 5.8 5.8