Partition of Sums of Squares in ANOVA (II)
Each of the blocks above contain sums of squares that summed over all values of i and j represent different sources of variation: total, between and within treatment variation.
In ANOVA we partition the total sum of squares (TSS) in:
Sums of squares due to treatments (SSTreat):
measures variation due to differences between treatments (explained variation).
with degrees of freedom t-1
Sums of squares error (SSE):
measures random variation within treatments (unexplained variation).
with degrees of freedom N-t