condition mean min max ZT0-3 6.97194534075 4.106372965 9.837517716499999 ZT4-7 14.22272862 12.71018553 15.73527171 ZT8-11 28.33462316 23.388114065 33.281132255 ZT12-15 27.613834335 24.039610395 31.188058275000003 ZT16-19 18.1913635925 17.777066685 18.6056605 ZT20-23 27.9948784675 22.568349425 33.42140751