Straight line drawn in the middle of a group of data points plotted on a scatter plot. It represents the results of data gathering on two variables and reflects if these two variables appear to be related to each other.

A more accurate procedure of determining the line of best fit is least squares method, a mathematical calculation. It is utilized in regression analysis that is the key input in statistical calculations such as sum of squares. Also, it can be used as a tool for evaluating trading activity or analyzing investment risk.