condition mean min max ZT0-3 3.6 3.6 3.6 ZT4-7 24.4 24.4 24.4 ZT8-11 18.05 18.05 18.05 ZT12-15 7.5 7.5 7.5 ZT16-19 22.75 22.75 22.75 ZT20-23 21.4 21.4 21.4