The statistical technique used in the regression analysis. The sum of squares is a mathematical approach to determining the dispersion of the data points. In a regression analysis the goal is to determine how well a data series can be fitted into a function which might help to explain how the data series was generated. The sum of squares is used as a mathematical way to find the function, which best fits from the data. In order to determine the sum of squares the distance between each data point and the line of the best fit is squared and then all of the squares are summed up. The line of the best fit will minimize this value?