Answer:
Sample means and the grand mean
Explanation:
The total sum of squares present in the sample can be partitioned into two parts.
1) Within sum of squares ( also called error sum of squares)
2) Between sum of squares
The first part is the sum of squares of deviations of the observations from the sample mean and is called the within sum of squares ( also called error sum of squares).
The second part is the weighted sum of the square of deviations of the sample means from the grand mean and is called between sum of squares.
Thus symbolically
Totastal SS = Within SS + Between SS