Brenda is the owner of a spa store that operates 50 weeks per year. spair shampoo is a high margin stock keeping unit (sku), but the product goes out of stock frequently. she decides to use a fixed-quantity system (fqs) and orders boxes of spair shampoo containing 10 bottles per box from a vendor 160 miles away. she collects the following data with respect to the sales of spair shampoo.