The height of the red square is the error of prediction and the area of the red square is the squared error of prediction. Therefore the height of the stacked squares is the sum of the errors of predi...The height of the red square is the error of prediction and the area of the red square is the squared error of prediction. Therefore the height of the stacked squares is the sum of the errors of prediction (the lengths of the lines are used, so all errors are positive) and the area of all squares is the total sum of squared errors. Adjust the line to see of you can make the squared error (area) as small as you can and note equation of the line and the size of the area.
