condition mean min max ZT0-3 10.236525 9.44585 11.0272 ZT4-7 10.73885 10.73885 10.73885 ZT8-11 10.368089999999999 10.368089999999999 10.368089999999999 ZT12-15 0 0 0 ZT16-19 13.2009 13.2009 13.2009 ZT20-23 12.34315 12.34315 12.34315