condition mean min max ZT0-3 1.4298761666666666 1.013842 1.7951515 ZT4-7 0.549569 0.549569 0.549569 ZT8-11 0.449612 0.449612 0.449612 ZT12-15 1.90523925 1.5718285 2.23865 ZT16-19 1.4976099999999999 1.4976099999999999 1.4976099999999999 ZT20-23 0.8402845000000001 0.8402845000000001 0.8402845000000001