condition mean min max ZT0-3 4.5 4.5 4.5 ZT4-7 1.6 1.6 1.6 ZT8-11 30.3 30.3 30.3 ZT12-15 2.85 2.85 2.85 ZT16-19 12.75 12.75 12.75 ZT20-23 21.55 21.55 21.55