To determine the cost function using this method, an analyst plots points on a scatter diagram, examines the diagram and estimates a line of best fit for the points.

Learn more about scatter diagrams with this BBC Bitesize Maths article. For students between the ages of 11 and 14.

In National 4 Maths learn how to draw a scatter diagram and a line of best fit. Use the diagram to help make predictions on future results.