condition mean min max ZT0-3 1.1 1.1 1.1 ZT4-7 1.0 1.0 1.0 ZT8-11 5.75 5.75 5.75 ZT12-15 2.8 2.8 2.8 ZT16-19 12.55 12.55 12.55 ZT20-23 1.7 1.7 1.7