condition mean min max ZT0-3 3.739931666666667 2.050615 4.7847100000000005 ZT4-7 2.4677249999999997 2.4677249999999997 2.4677249999999997 ZT8-11 2.937865 2.937865 2.937865 ZT12-15 3.969765 3.6300850000000002 4.309445 ZT16-19 7.2772950000000005 7.2772950000000005 7.2772950000000005 ZT20-23 4.6950199999999995 4.6950199999999995 4.6950199999999995