condition mean min max ZT0-3 21.5 21.5 21.5 ZT4-7 9.6 9.6 9.6 ZT8-11 18.75 18.75 18.75 ZT12-15 21.15 21.15 21.15 ZT16-19 25.6 25.6 25.6 ZT20-23 18.5 18.5 18.5