condition mean min max ZT0-3 24.627516666666665 21.9425 26.07895 ZT4-7 17.818800000000003 17.818800000000003 17.818800000000003 ZT8-11 11.39735 11.39735 11.39735 ZT12-15 15.42245 15.08305 15.761849999999999 ZT16-19 15.1639 15.1639 15.1639 ZT20-23 20.625799999999998 20.625799999999998 20.625799999999998