condition mean min max ZT0-3 2.73369825075 2.614904868 2.8524916334999997 ZT4-7 4.677534607749999 3.4646256145 5.890443600999999 ZT8-11 9.686950653250001 8.957956008 10.4159452985 ZT12-15 12.7954466425 11.095398315 14.49549497 ZT16-19 13.9257796875 13.31377019 14.537789185 ZT20-23 13.352014902499999 13.29801392 13.406015884999999