condition mean min max ZT0-3 2.67676746425 1.7650032569999998 3.5885316715 ZT4-7 9.2890233685 5.4566074874999995 13.1214392495 ZT8-11 21.881990039999998 16.35265523 27.41132485 ZT12-15 28.34518609 27.967512114999998 28.722860065 ZT16-19 20.3846531525 19.26057002 21.508736284999998 ZT20-23 21.9417772175 21.38676568 22.496788755