condition mean min max ZT0-3 21.099999999999998 21.099999999999998 21.099999999999998 ZT4-7 6.2 6.2 6.2 ZT8-11 16.0 16.0 16.0 ZT12-15 11.85 11.85 11.85 ZT16-19 2.3 2.3 2.3 ZT20-23 17.4 17.4 17.4