4. A manager of a large chain of appliance stores is planning to conduct a pricing experiment to determine the price elasticity of the chain's line of microwave ovens. He plans to measure sales for the month of February, raise prices by 12 percent on March 15, and then measure sales for the month of April. Each sales measurement would take into account the total monthly microwave oven sales for all of the stores in his chain. He has asked you to evaluate his research procedure and suggest any improvements. What would you suggest