The shortest processing time rule is a prioritization rule that assigns the highest priority to the job that requires the least amount of processing time. This rule minimizes the average flow time of jobs and reduces the number of jobs in queue. The critical ratio rule assigns priority based on the ratio of time remaining until the due date to the remaining processing time. The fewest operations remaining rule assigns priority based on the number of remaining operations for each job. The first come, first served rule assigns priority based on the arrival time of the jobs. References: Managing Supply Chain Operations, Chapter 9: Scheduling and Sequencing, page 237. Manufacturing Planning and Control for Supply Chain Management: The CPIM Reference, Second Edition, Chapter 13: Scheduling and Execution, page 419.

Safety stock is the extra inventory that a company keeps to prevent stockouts or shortages due to uncertainties in demand, supply, or lead time. Safety stock acts as a buffer to protect the company from losing sales or disrupting operations. One of the factors that is used to determine safety stock is the forecast error distribution, which is the measure of how much the actual demand deviates from the forecasted demand.
Forecast error distribution can be calculated by using statistical methods, such as standard deviation or mean absolute deviation, to find the average and the variability of the forecast errors. The higher the forecast error distribution, the more safety stock is needed to cover the potential demand fluctuations. Forecast error distribution is one of the components of the safety stock formula, which is:
Safety stock = Z x #LT x D
Where:
Z refers to the service level factor, which is the desired probability of not having a stockout.
#LT refers to the standard deviation of lead time, which is the average variability of the time it takes to replenish inventory.
D is the average demand per unit of time.
References := CPIM Part 2 Exam Content Manual, Version 8.0, ASCM, 2021, p. 24. CPIM Part 2 Learning System, Version 8.0, Module 2, Section C, Topic 3. How To Calculate Safety Stock (With Examples and FAQs). What is Safety Stock? (Definition, Formulas, Best Practices).

In inflationary environments, LIFO assigns the most recent (higher) costs to the cost of goods sold, resulting in higher COGS and lower taxable income. FIFO does the opposite, leading to lower COGS and higher profits.
"When inflation occurs, the LIFO method results in higher cost of goods sold because it uses more recent, higher-cost inventory values."
- CPIM Practice Questions, Inventory Valuation (DSP Page 97)

A company that uses two-level master scheduling has a master production schedule (MPS) for the end items (kits) and a final assembly schedule (FAS) for the components (tools). The forecasts that are input to master scheduling should reflect the total number of kits and the specific kit configurations, as these determine the demand for the components. The other options are not relevant for master scheduling, as they do not reflect the end item demand or the bill of materials structure. References: EXAM CONTENT MANUAL PREVIEW, page 10, section 4.1.2. Manufacturing Planning and Control for Supply Chain Management: The CPIM Reference, Second Edition, page 163, section 6.2.

Mixed-model scheduling is a technique that allows multiple products to be produced on the same assembly line without changeovers, and then sequences those products in a way that smoothes the demand for upstream components12. In this case, the company is using mixed-model scheduling to produce three different products (A, B, and C) on the same line, and then alternating them in a pattern that minimizes the variation in the workload and the inventory levels. The other options are not correct because:
*Matrix scheduling is a technique that assigns tasks to workers based on their skills and availability3.
*Synchronized scheduling is a technique that coordinates the production and delivery of materials and components to match the demand of the final assembly4.
*Line balancing is a technique that distributes the workload evenly among the workers or machines on a production line5. References := 1 Create Mixed Model Flow in 5 Steps | Industrial Equipment News 2 Mixed Model Scheduling - Mountain Home Academy 3 Matrix Scheduling - an overview | ScienceDirect Topics 4 Synchronized Scheduling - an overview | ScienceDirect Topics 5 Line Balancing - an overview | ScienceDirect Topics