condition mean min max ZT0-3 1.7313866666666666 1.52447 1.8667500000000001 ZT4-7 2.5948200000000003 2.5948200000000003 2.5948200000000003 ZT8-11 3.37491 3.37491 3.37491 ZT12-15 7.850499999999999 7.25991 8.441089999999999 ZT16-19 5.17229 5.17229 5.17229 ZT20-23 3.797315 3.797315 3.797315