condition mean min max ZT0-3 3.9 3.9 3.9 ZT4-7 20.8 20.8 20.8 ZT8-11 22.5 22.5 22.5 ZT12-15 17.25 17.25 17.25 ZT16-19 22.1 22.1 22.1 ZT20-23 3.65 3.65 3.65