condition mean min max ZT0-3 1.3733270000000002 0.588401 2.1399350000000004 ZT4-7 0.3645425 0.3645425 0.3645425 ZT8-11 1.20778 1.20778 1.20778 ZT12-15 2.5635499999999998 2.4850849999999998 2.642015 ZT16-19 1.70814 1.70814 1.70814 ZT20-23 2.7298099999999996 2.7298099999999996 2.7298099999999996