condition mean min max ZT0-3 3.368984354 2.963202232 3.774766476 ZT4-7 2.42998885475 2.055695067 2.8042826425 ZT8-11 2.587849804 2.3510325520000004 2.824667056 ZT12-15 3.22322862925 3.0539838495 3.392473409 ZT16-19 6.20171395625 4.201515911 8.201912001499998 ZT20-23 17.0412676425 12.850909715 21.23162557