condition mean min max ZT0-3 2.8667233333333333 2.263515 3.34595 ZT4-7 2.67976 2.67976 2.67976 ZT8-11 1.53315 1.53315 1.53315 ZT12-15 4.337455 4.23968 4.43523 ZT16-19 5.502825 5.502825 5.502825 ZT20-23 5.392799999999999 5.392799999999999 5.392799999999999