condition mean min max ZT0-3 4.567878447 2.820860807 6.314896087 ZT4-7 9.8204172245 8.614725394499999 11.026109054500001 ZT8-11 10.82117685325 9.5464207515 12.095932955 ZT12-15 9.859554073000002 9.834622418 9.884485728000001 ZT16-19 11.038011164250001 9.4667015735 12.609320755 ZT20-23 21.2871721375 16.945932555 25.628411720000003