condition mean min max ZT0-3 2.75 2.75 2.75 ZT4-7 15.2 15.2 15.2 ZT8-11 5.15 5.15 5.15 ZT12-15 4.6 4.6 4.6 ZT16-19 8.9 8.9 8.9 ZT20-23 2.0 2.0 2.0