condition mean min max ZT0-3 0.3929725 0.31122099999999997 0.47472400000000003 ZT4-7 0.63748 0.63748 0.63748 ZT8-11 0.743576 0.743576 0.743576 ZT12-15 0 0 0 ZT16-19 0.8809990000000001 0.8809990000000001 0.8809990000000001 ZT20-23 0.469798 0.469798 0.469798