The SD line goes through the point of averages, and has slope equal to SD_Y/SD_X if the correlation coefficient r is greater than or equal to zero. The SD line has slope −SD_Y/SD_X if r is negative. That is, the SD line climbs (sinks, if r is negative) by SD_Y when you move to the right by SD_X. The sign of the slope of theSD line is the same as the sign of r, and the size of the slope of the SD line is SD_Y/SD_X. In standard units, the slope of the SD line is one if r is greater than or equal to zero, and equal to minus one if r is negative. If SD_X is zero, the SD line is not defined

SD line : 표준편차선

correlation coefficient r = 상관계수 r

입니다. that is 부터 무슨말인지 멘붕중이에요ㅠㅠ