condition mean min max ZT0-3 2.8 2.8 2.8 ZT4-7 12.4 12.4 12.4 ZT8-11 23.4 23.4 23.4 ZT12-15 24.85 24.85 24.85 ZT16-19 21.35 21.35 21.35 ZT20-23 4.75 4.75 4.75