condition mean min max ZT0-3 3.33140218675 3.2869142335 3.37589014 ZT4-7 2.44649493125 2.15212028 2.7408695825000002 ZT8-11 2.839030426 2.5555341469999995 3.1225267050000003 ZT12-15 3.0584188155 2.4650808445 3.6517567865 ZT16-19 1.8072374972500003 1.485981471 2.1284935235000004 ZT20-23 4.0307146615 3.4595740655 4.6018552575000005