condition mean min max ZT0-3 21.9388 11.59985 28.259349999999998 ZT4-7 9.607925 9.607925 9.607925 ZT8-11 7.845174999999999 7.845174999999999 7.845174999999999 ZT12-15 11.0179925 9.762485000000002 12.273499999999999 ZT16-19 15.2106 15.2106 15.2106 ZT20-23 29.15935 29.15935 29.15935