condition mean min max ZT0-3 3.9290989817499997 3.099765466 4.758432497499999 ZT4-7 3.91047037875 3.8178098164999996 4.003130941 ZT8-11 3.7030300242500003 3.2397227415 4.166337307 ZT12-15 5.880345104250001 5.1410077245000005 6.619682484 ZT16-19 12.1780867935 9.593554397 14.76261919 ZT20-23 21.7495848775 20.2180463 23.281123455