condition mean min max ZT0-3 8.75 8.75 8.75 ZT4-7 2.8 2.8 2.8 ZT8-11 15.75 15.75 15.75 ZT12-15 20.4 20.4 20.4 ZT16-19 35.5 35.5 35.5 ZT20-23 33.6 33.6 33.6