condition mean min max ZT0-3 1.6844363333333332 0.973715 2.29948 ZT4-7 1.1926929999999998 1.1926929999999998 1.1926929999999998 ZT8-11 1.91624 1.91624 1.91624 ZT12-15 5.4799775 4.37684 6.583115 ZT16-19 5.940075 5.940075 5.940075 ZT20-23 3.3863649999999996 3.3863649999999996 3.3863649999999996