Illustration of sums of squares


This diagram shows how to interpret the total, between-groups and within-groups sums of squares. Each can be visualised as the sum of certain squared lines on the scatterplot.

Click the green, red and blue dot plots on the right to see the individual components (as coloured lines on the scatterplot on the left) whose sum of squares gives the relevant value in the formula above.

Use the slider to change the data and explain that lower the relative size of the between-group sum of squares (compared to the within-group sum of squares), the weaker the evidence of a real difference between the groups.