condition mean min max ZT0-3 10.194178333333333 5.173465 14.923449999999999 ZT4-7 4.70824 4.70824 4.70824 ZT8-11 6.7360500000000005 6.7360500000000005 6.7360500000000005 ZT12-15 9.8952525 8.747625 11.04288 ZT16-19 13.87375 13.87375 13.87375 ZT20-23 20.93255 20.93255 20.93255