condition mean min max ZT0-3 5.9 5.9 5.9 ZT4-7 4.9 4.9 4.9 ZT8-11 3.55 3.55 3.55 ZT12-15 6.5 6.5 6.5 ZT16-19 18.3 18.3 18.3 ZT20-23 2.7 2.7 2.7