condition mean min max ZT0-3 0.7425221666666667 0.26808 1.469225 ZT4-7 0.727855 0.727855 0.727855 ZT8-11 1.231112 1.231112 1.231112 ZT12-15 0.365738 0.23982 0.491656 ZT16-19 1.403035 1.403035 1.403035 ZT20-23 1.32372 1.32372 1.32372