condition mean min max ZT0-3 4.1 4.1 4.1 ZT4-7 2.8 2.8 2.8 ZT8-11 6.35 6.35 6.35 ZT12-15 47.099999999999994 47.099999999999994 47.099999999999994 ZT16-19 10.65 10.65 10.65 ZT20-23 2.0 2.0 2.0