condition mean min max ZT0-3 2.1 2.1 2.1 ZT4-7 1.2 1.2 1.2 ZT8-11 20.05 20.05 20.05 ZT12-15 3.9 3.9 3.9 ZT16-19 20.4 20.4 20.4 ZT20-23 3.55 3.55 3.55