condition mean min max ZT0-3 1.6 1.6 1.6 ZT4-7 3.0 3.0 3.0 ZT8-11 10.0 10.0 10.0 ZT12-15 2.25 2.25 2.25 ZT16-19 2.8 2.8 2.8 ZT20-23 2.1 2.1 2.1