condition mean min max ZT0-3 13.75 13.75 13.75 ZT4-7 4.4 4.4 4.4 ZT8-11 0.9 0.9 0.9 ZT12-15 8.0 8.0 8.0 ZT16-19 1.4 1.4 1.4 ZT20-23 2.2 2.2 2.2