condition mean min max ZT0-3 2.001861395 1.1506781609999999 2.853044629 ZT4-7 6.10084068725 3.710992732 8.4906886425 ZT8-11 17.735499162500002 13.671172595000002 21.799825730000002 ZT12-15 21.869261365 19.865874735 23.872647995 ZT16-19 17.498745980000002 16.921785980000003 18.07570598 ZT20-23 18.281063155 18.175909575 18.386216734999998