Answer:
When using ANOVA, the sum of squares within is:  Showing the difference between the Total SS and Between SS known as Error variance 
Step-by-step explanation:
Within SS is also known as Error sum of squares . It is calculated by finding the difference between Total Sum of Squares and Between Sum of Squares
with the given degrees of freedom.
Within SS = Total SS - Between SS
Where
Total SS= ∑∑X²- C. F 
Between SS= ∑T²j/r - C.F 
Correction Factor = CF = Tj²/n
So the correct answer would be 
Showing the difference between the Total SS and Between SS also known as   Error variance.