condition mean min max ZT0-3 7.3 7.3 7.3 ZT4-7 28.7 28.7 28.7 ZT8-11 18.95 18.95 18.95 ZT12-15 21.05 21.05 21.05 ZT16-19 9.65 9.65 9.65 ZT20-23 20.6 20.6 20.6