condition mean min max ZT0-3 58.287537 58.287537 58.287537 ZT4-7 18.0714015 18.0714015 18.0714015 ZT8-11 16.889919499999998 16.889919499999998 16.889919499999998 ZT12-15 21.229241000000002 21.229241000000002 21.229241000000002 ZT16-19 26.1649825 26.1649825 26.1649825 ZT20-23 45.3070855 45.3070855 45.3070855