condition mean min max ZT0-3 6.55 6.55 6.55 ZT4-7 8.6 8.6 8.6 ZT8-11 23.75 23.75 23.75 ZT12-15 29.75 29.75 29.75 ZT16-19 5.7 5.7 5.7 ZT20-23 37.05 37.05 37.05