condition mean min max ZT0-3 2.3835100000000002 2.3835100000000002 2.3835100000000002 ZT4-7 0.6119330000000001 0.6119330000000001 0.6119330000000001 ZT8-11 1.1075949999999999 1.1075949999999999 1.1075949999999999 ZT12-15 2.81852 2.81852 2.81852 ZT16-19 5.9606650000000005 5.9606650000000005 5.9606650000000005 ZT20-23 4.178455 4.178455 4.178455