condition mean min max ZT0-3 2.380415 2.380415 2.380415 ZT4-7 3.580825 3.580825 3.580825 ZT8-11 2.5337300000000003 2.5337300000000003 2.5337300000000003 ZT12-15 1.8905850000000002 1.8905850000000002 1.8905850000000002 ZT16-19 2.137085 2.137085 2.137085 ZT20-23 2.155395 2.155395 2.155395