condition mean min max ZT0-3 1.3722083333333333 1.166795 1.5860699999999999 ZT4-7 1.2744 1.2744 1.2744 ZT8-11 1.1253454999999999 1.1253454999999999 1.1253454999999999 ZT12-15 1.1207112499999998 1.0792899999999999 1.1621325 ZT16-19 1.0742005 1.0742005 1.0742005 ZT20-23 1.37339 1.37339 1.37339