condition mean min max ZT0-3 20.8 20.8 20.8 ZT4-7 3.2 3.2 3.2 ZT8-11 21.099999999999998 21.099999999999998 21.099999999999998 ZT12-15 16.5 16.5 16.5 ZT16-19 6.85 6.85 6.85 ZT20-23 31.9 31.9 31.9