condition mean min max ZT0-3 33.95 33.95 33.95 ZT4-7 6.5 6.5 6.5 ZT8-11 2.7 2.7 2.7 ZT12-15 20.15 20.15 20.15 ZT16-19 4.75 4.75 4.75 ZT20-23 9.9 9.9 9.9