condition mean min max ZT0-3 747.924364 747.924364 747.924364 ZT4-7 825.962583 825.962583 825.962583 ZT8-11 509.97530500000005 509.97530500000005 509.97530500000005 ZT12-15 361.8262005 361.8262005 361.8262005 ZT16-19 330.68080799999996 330.68080799999996 330.68080799999996 ZT20-23 395.49411599999996 395.49411599999996 395.49411599999996