condition mean min max ZT0-3 492.091845 492.091845 492.091845 ZT4-7 546.8357995 546.8357995 546.8357995 ZT8-11 721.758961 721.758961 721.758961 ZT12-15 671.2448414999999 671.2448414999999 671.2448414999999 ZT16-19 730.5794455 730.5794455 730.5794455 ZT20-23 829.320451 829.320451 829.320451