condition mean min max ZT0-3 29.851906 29.851906 29.851906 ZT4-7 39.7495865 39.7495865 39.7495865 ZT8-11 37.8283005 37.8283005 37.8283005 ZT12-15 33.839475 33.839475 33.839475 ZT16-19 28.9024405 28.9024405 28.9024405 ZT20-23 23.750687499999998 23.750687499999998 23.750687499999998