## Partitioning Sums of Squares

This section discusses the sums of squares, including partitioning sum of squares into sums of squares predicted and sum of squares error.

### Answers

- To compute a deviation score you subtract the mean. 15 - 10 = 5.
- To compute SSY, first compute the deviation scores (y) by subtracting
the mean (10) from each number. Then square these values and add them
together: (-8)
^{2}+ (-1)^{2}+ 1^{2}+ 3^{2}+ 5^{2}= 100 - SSY = SSY' + SSE; SSE = SSY - SSY' = 25.5 - 18.3 = 7.2
- Proportion of variation explained = SSY'/SSY, so as SSY' increases, so does the proportion of variation explained.
- Proportion explained = SSY'/SSY; SSY' = (.3)(20) = 6
- r
^{2}is the proportion of variation explained. (.84)^{2}= .71