condition mean min max ZT0-3 2.3685833333333335 1.37375 3.26465 ZT4-7 1.9775800000000001 1.9775800000000001 1.9775800000000001 ZT8-11 2.259915 2.259915 2.259915 ZT12-15 2.927085 2.0542550000000004 3.799915 ZT16-19 3.76137 3.76137 3.76137 ZT20-23 3.68912 3.68912 3.68912