Petromax Enterprises uses a continuous review inventory control system for one of its SKUs. The following information is available on the item. The firm operates 52 weeks in a year. Refer to the standard normal table for z-values. > Demand =52,000 units/year > Ordering cost =$38.50 /order > Holding cost =$3.50/ unit/year > Average lead time =4 weeks > Standard deviation of weekly demand =225 units a. The economic order quantity for this item is units. (Enter your response rounded to the nearest whole number.) Nationwide Auto Parts uses a periodic review inventory control system for one of its stock items. The review interval is 9 weeks, and the lead time for receiving the materials ordered from its wholesaler is 4 weeks. Weekly demand is normally distributed, with a mean of 250 units and a standard deviation of 50 units. Refer to the standard normal table for z-values. a. What is the average and the standard deviation of demand during the protection interval? The average demand during the protection interval is units. (Enter your response as an integer.)