The line on the scatter plot presented below represents the regression line or "line of best fit". While the correlation coefficient provides a single numerical estimate of the relationship between two variables, the regression line gives a visual presentation of this relationship. We can use the regression line to predict a value of "Y" for any "X" score. The steepness of the angle of the regression line is called its slope. It is the amount of change in "Y" that we can expect for any unit change in "X".