condition mean min max ZT0-3 3.0510083333333333 2.62968 3.3322450000000003 ZT4-7 3.21911 3.21911 3.21911 ZT8-11 4.71097 4.71097 4.71097 ZT12-15 5.5359 4.665255 6.4065449999999995 ZT16-19 7.6199650000000005 7.6199650000000005 7.6199650000000005 ZT20-23 4.554945 4.554945 4.554945