condition mean min max ZT0-3 2.70134 2.70134 2.70134 ZT4-7 1.6628949999999998 1.6628949999999998 1.6628949999999998 ZT8-11 1.9010500000000001 1.9010500000000001 1.9010500000000001 ZT12-15 2.0140450000000003 2.0140450000000003 2.0140450000000003 ZT16-19 4.5441 4.5441 4.5441 ZT20-23 2.652 2.652 2.652