The results of a two-factor, independent-measures, equal n experiment are summarized in the following matrix. The numerical value in each cell is the mean score obtained from the sample in that treatment condition.

B₁ B₂
A₁ M=4 M=10
A₂ M=4 M=2

Compute the overall means for the scores in A₁, the scores in A₂, the scores in B₁, and the scores in B₂. Enter each of the means to the right of the appropriate row or below the appropriate column in the matrix.