condition mean min max ZT0-3 5.7 5.7 5.7 ZT4-7 2.3 2.3 2.3 ZT8-11 4.4 4.4 4.4 ZT12-15 2.4 2.4 2.4 ZT16-19 4.55 4.55 4.55 ZT20-23 21.05 21.05 21.05