condition mean min max ZT0-3 6.24422 6.24422 6.24422 ZT4-7 5.38976 5.38976 5.38976 ZT8-11 6.863300000000001 6.863300000000001 6.863300000000001 ZT12-15 7.8939449999999995 7.8939449999999995 7.8939449999999995 ZT16-19 12.254249999999999 12.254249999999999 12.254249999999999 ZT20-23 8.465175 8.465175 8.465175