condition mean min max ZT0-3 2.6129603704999997 2.3572604939999997 2.8686602469999998 ZT4-7 1.6044021960000001 1.368990985 1.839813407 ZT8-11 2.3876461715 2.0121328099999998 2.7631595330000005 ZT12-15 2.6986666150000005 2.3623829520000004 3.034950278 ZT16-19 2.7224456024999997 2.261710675 3.18318053 ZT20-23 5.49644297675 4.610812595 6.3820733585000005