condition mean min max ZT0-3 4.6 4.6 4.6 ZT4-7 2.1 2.1 2.1 ZT8-11 3.9 3.9 3.9 ZT12-15 3.8 3.8 3.8 ZT16-19 33.65 33.65 33.65 ZT20-23 2.5 2.5 2.5