condition mean min max ZT0-3 18.4 18.4 18.4 ZT4-7 12.9 12.9 12.9 ZT8-11 12.1 12.1 12.1 ZT12-15 25.5 25.5 25.5 ZT16-19 15.15 15.15 15.15 ZT20-23 22.35 22.35 22.35