condition mean min max ZT0-3 2.2 2.2 2.2 ZT4-7 3.0 3.0 3.0 ZT8-11 5.0 5.0 5.0 ZT12-15 4.8 4.8 4.8 ZT16-19 4.25 4.25 4.25 ZT20-23 5.3 5.3 5.3