Given the following data for a particular product calculate the optimal service level. Sales response rate is 0.15% change in revenue for a 1% change in the service level (fill rate). Trading margin is $14 per item; inventory-carrying cost is 30% per year, annual sales through the warehouse is 90,000 items. Cost of each item is $50, demand standard deviation is 450 items for a week, and the lead-time is 5 weeks.
a. Calculate Delta_P
b. Calculate Delta_C
c. Calculate Delta_Z
d. Determine the optimal service level