condition mean min max ZT0-3 12.058741 12.058741 12.058741 ZT4-7 12.619764 12.619764 12.619764 ZT8-11 13.106488500000001 13.106488500000001 13.106488500000001 ZT12-15 12.588027499999999 12.588027499999999 12.588027499999999 ZT16-19 13.362567 13.362567 13.362567 ZT20-23 13.611867 13.611867 13.611867