In this module, we extend the learnings from the previous module to more complex scenarios of inventory management, namely, when demand is uncertain and cannot be predicted with certainty. First, we learn how to measure uncertainty in demand using demand distributions – particularly the Normal distribution, which is the more common demand distribution used in practice. Second, we will learn about the decision tradeoffs in managing inventory with uncertainty, namely, between service levels and costs of inventory. The key decisions related to managing inventory with demand uncertainty are order quantity, reorder point, safety or buffer stock levels, and frequency of inventory review and ordering. Upon completion of this module, we will gain knowledge and expertise in making these decisions optimally using different inventory policies such as continuous review policy and periodic review policy. This module is important for managing inventories in most operations settings in an efficient and effective manner.