condition mean min max ZT0-3 2.1509 1.7393299999999998 2.5624700000000002 ZT4-7 3.170865 3.170865 3.170865 ZT8-11 2.37684 2.37684 2.37684 ZT12-15 0 0 0 ZT16-19 2.58829 2.58829 2.58829 ZT20-23 2.203765 2.203765 2.203765