Dental pain relief
Use this diagram to explain the values of the treatment and block sums of squares.
It initially shows the differences whose sum of squares is the treatment sum of squares.
Select Block sum of squares to display differences whose sum of squares is the block sum of squares.
Pain relief score were measured for 32 subjects who were each given one of four treatments (combinations of codeine and acupuncture). They were grouped into blocks of four according to an initial assessment of their pain tolerance and the treatments were randomly allocated to the four subjects in each block. (I.e. a randomised block design was used.)