condition mean min max ZT0-3 4.508146666666667 3.48877 5.5944400000000005 ZT4-7 2.926695 2.926695 2.926695 ZT8-11 1.369993 1.369993 1.369993 ZT12-15 6.3677775 4.301155 8.4344 ZT16-19 7.533635 7.533635 7.533635 ZT20-23 7.045120000000001 7.045120000000001 7.045120000000001