1. Notice how the sum of squares total is divided up into the sum of squared differences of each score from its group mean and the sum of squared differences of the group mean from the grand mean (GM: the mean of all data). Keep in mind that differences of group means from the grand mean have to be multiplied by the sample size.
   
   
2. Add a few data points by clicking and note the effects on the sums of squares. Notice that if the points are far from the group mean then the sum of squares within increases greatly.
   
   
3. Choose dataset 2. Notice that the means are very different and the data points are all near their group mean. This results in a large sum of squares between and a msall sum of squares within.
   
   
4. Look at data set 4 which is similar but has more subjects.
   
   
5. Look at dataset 6 for which the group means are all the same. Note the value of the sum of squares between.
   
   
6. Choose "blank dataset" and enter your own data.