condition mean min max ZT0-3 2.658198984916667 2.3060454223333333 3.0103525475 ZT4-7 2.0014476161666668 1.8488505046666666 2.1540447276666668 ZT8-11 3.94671855 3.4880846869999997 4.405352413 ZT12-15 3.8905868459999997 3.560251346 4.220922346 ZT16-19 3.2861941105000003 3.251449671 3.32093855 ZT20-23 2.708377495 2.655033592 2.761721398