condition mean min max ZT0-3 4.713666666666667 3.9642800000000005 5.39706 ZT4-7 5.824585 5.824585 5.824585 ZT8-11 10.764595 10.764595 10.764595 ZT12-15 14.062175 13.687850000000001 14.4365 ZT16-19 17.680349999999997 17.680349999999997 17.680349999999997 ZT20-23 13.95555 13.95555 13.95555