Valuing Inventory Using Average Cost Retail Method Dean Company uses the retail inventory method to estimate its inventory for interim statement disclosures. Data relating to the computation of inventory at July 31 follow. Required Compute estimated inventory on July 31 using the average cost retail method. - Note: Use negative signs as appropriate in the following schedule. Required Compute estimated inventory on July 31 using the average cost retail method. - Note: Use negative signs as appropriate in the following schedule