condition mean min max ZT0-3 6.4 6.4 6.4 ZT4-7 6.6 6.6 6.6 ZT8-11 2.45 2.45 2.45 ZT12-15 4.8 4.8 4.8 ZT16-19 6.15 6.15 6.15 ZT20-23 3.0 3.0 3.0