condition mean min max ZT0-3 1.58788 1.58788 1.58788 ZT4-7 4.1434999999999995 4.1434999999999995 4.1434999999999995 ZT8-11 1.6871200000000002 1.6871200000000002 1.6871200000000002 ZT12-15 1.480555 1.480555 1.480555 ZT16-19 2.074412 2.074412 2.074412 ZT20-23 3.7182966666666664 3.7182966666666664 3.7182966666666664