condition mean min max ZT0-3 6.5 6.5 6.5 ZT4-7 14.7 14.7 14.7 ZT8-11 15.1 15.1 15.1 ZT12-15 35.9 35.9 35.9 ZT16-19 15.95 15.95 15.95 ZT20-23 30.05 30.05 30.05