condition mean min max ZT0-3 6.05 6.05 6.05 ZT4-7 1.6 1.6 1.6 ZT8-11 2.2 2.2 2.2 ZT12-15 1.95 1.95 1.95 ZT16-19 3.0 3.0 3.0 ZT20-23 8.85 8.85 8.85