There are many techniques for solving Multi-Objective Optimization (MOO) problems. Goal programming, Weighted sum method, lexicographic method, and ?-constraints method are popularly used for solving MOO problems. Under the weighted sum method, a combined objective function is formulated to solve the MOO problems. Correlation, Mean, Median, Average, New Average, Optimal average techniques have been proposed to solve the MOO problems. These techniques have not been formulated appropriately. The application of these techniques has been demonstrated with inferior examples. The solution of these techniques has also not been interpreted appropriately. The misconceptions of these techniques have been clarified in this paper. The solutions of these techniques have also been compared with Sen's MOO technique.