condition mean min max ZT0-3 12.55353647075 11.6460464715 13.46102647 ZT4-7 7.31216360175 6.936753102 7.6875741015 ZT8-11 5.847029849249999 5.2945718305 6.399487868 ZT12-15 10.983320871 7.361481207 14.605160535 ZT16-19 18.457178272500002 15.33918861 21.575167935000003 ZT20-23 25.806971705000002 23.126118455 28.487824955