condition mean min max ZT0-3 12.65 12.65 12.65 ZT4-7 18.0 18.0 18.0 ZT8-11 3.55 3.55 3.55 ZT12-15 2.65 2.65 2.65 ZT16-19 23.25 23.25 23.25 ZT20-23 21.5 21.5 21.5