condition mean min max ZT0-3 23.347628 23.347628 23.347628 ZT4-7 19.9820645 19.9820645 19.9820645 ZT8-11 21.351090499999998 21.351090499999998 21.351090499999998 ZT12-15 22.930675 22.930675 22.930675 ZT16-19 22.084289 22.084289 22.084289 ZT20-23 21.5172935 21.5172935 21.5172935