condition mean min max ZT0-3 1.1 1.1 1.1 ZT4-7 2.1 2.1 2.1 ZT8-11 3.25 3.25 3.25 ZT12-15 1.6 1.6 1.6 ZT16-19 1.35 1.35 1.35 ZT20-23 1.9 1.9 1.9