condition mean min max ZT0-3 8.085300707 6.150269624 10.02033179 ZT4-7 2.601200721 2.4426505570000003 2.759750885 ZT8-11 3.64894774475 3.0841220620000005 4.2137734275 ZT12-15 3.972674895 3.9337982005 4.0115515895 ZT16-19 10.855608160500001 6.3457513975 15.365464923500001 ZT20-23 35.739604637499994 24.98934311 46.489866164999995