condition mean min max ZT0-3 1.7 1.7 1.7 ZT4-7 0.7 0.7 0.7 ZT8-11 2.1 2.1 2.1 ZT12-15 3.7 3.7 3.7 ZT16-19 6.95 6.95 6.95 ZT20-23 2.6 2.6 2.6