condition mean min max ZT0-3 2.9 2.9 2.9 ZT4-7 1.1 1.1 1.1 ZT8-11 3.5 3.5 3.5 ZT12-15 2.0 2.0 2.0 ZT16-19 1.65 1.65 1.65 ZT20-23 2.75 2.75 2.75