The total number of degrees of freedom is n-1 as there is only one restriction of computing the grand mean. The d.f for k samples is k-1 beacuase the mean of the sample means must equal the grand mean. Similarly , the d.f for within SS is n-k , due to the k restrictions of computing the k sample means. Hence we find that
Total df= Within df + Between df
n-1= (n-k)+(k-1)
Between SS has (k-1) d.f
Within SS has (n-k) d.f
These two quantities are known as mean squares and has d.f (n-1)
