condition mean min max ZT0-3 6.9 6.9 6.9 ZT4-7 24.9 24.9 24.9 ZT8-11 12.75 12.75 12.75 ZT12-15 40.0 40.0 40.0 ZT16-19 35.15 35.15 35.15 ZT20-23 15.7 15.7 15.7