condition mean min max ZT0-3 3.35 3.35 3.35 ZT4-7 4.9 4.9 4.9 ZT8-11 2.1 2.1 2.1 ZT12-15 4.2 4.2 4.2 ZT16-19 5.0 5.0 5.0 ZT20-23 6.7 6.7 6.7