The slope of a straight line tells us how steep the line is, and can be calculated by dividing the rise of the line by its run. The are many forms for the equation of a line, but in statistics the slope-intercept form is used most often. Although working directly with this type of equation is first encountered in algebra, it is good to have a good handle on the basics of straight lines. Straight lines occur in statistics when working with least-squares regression lines. The slope of the regression line is a quantity that can be analyzed statistically.