condition mean min max ZT0-3 3.803595 3.1788499999999997 4.40085 ZT4-7 1.8127849999999999 1.8127849999999999 1.8127849999999999 ZT8-11 2.650535 2.650535 2.650535 ZT12-15 3.1307125 3.04823 3.213195 ZT16-19 3.4534900000000004 3.4534900000000004 3.4534900000000004 ZT20-23 3.78845 3.78845 3.78845