condition mean min max ZT0-3 15.341971 15.341971 15.341971 ZT4-7 13.4486795 13.4486795 13.4486795 ZT8-11 14.6305215 14.6305215 14.6305215 ZT12-15 22.162595500000002 22.162595500000002 22.162595500000002 ZT16-19 12.9145865 12.9145865 12.9145865 ZT20-23 9.209516 9.209516 9.209516