condition mean min max ZT0-3 4.2639972505 3.336464186 5.191530315 ZT4-7 7.743388049249999 6.2120878694999995 9.274688228999999 ZT8-11 12.665585931499999 11.037302282999999 14.293869579999999 ZT12-15 16.622951987500002 15.38582056 17.860083415000002 ZT16-19 15.0289381175 13.176159564999999 16.88171667 ZT20-23 22.722356204999997 20.442816765 25.001895644999998