Master Planning of Resources (APICS Exam #2)

What are the three things that can be controlled by a Firm Planned Order?

1) the bill of material 2) the start day 3) the end date 4) the quantity 5) the routing CANNOT CHANGE THE ORDER NUMBER

Estimating demand at each final distribution center based on historical demand and summing the total is forecasting by which of the following? a) Aggregation b) Allocation c) Intermediary d) Channel

Aggregation - Aggregation is estimating demand by final distribution sites and summing the total. - Allocation is forecasting the total sales worldwide by number of units - Intermediaries are channels in the distribution process, not a forecasting method - Channels are distribution mechanisms, not a forecasting method

Pull systems of planning and control in a distribution environment: a) allow each distribution center to manage its own inventory b) centralize inventory management c) rely on replenishment orders from the stocking locations closest to the production facilities d) are centralized at the first level in distribution and the first level in production and are decentralized at every other point

Allow each distribution center to manage its own inventory - With a pull system, a distribution center replenishes inventory based upon its own demand and supply parameters - Centralized inventory management pushes inventory out to the distribution centers - Pull systems are based on demand closest to the customer, not closest to production - There is no centralization of inventory management in a pull system of planning and control

Which of the following describes the planning horizon? a) Amount of time it takes to conduct the planning process b) Maximum amount of lead time required to order and receive all purchased materials required c) Two years' long d) Amount of time a plan extends into the future

Amount of time a plan extends into the future - Planning Horizon: "amount of time a plan extends into the future" - Length of planning horizon varies depending on the particular planning activity taking place

Adding a distributor as a channel between manufacturers and retailers will result in all of the following EXCEPT: a) a decrease in the number of transactions for retailers b) a decrease in transportation costs c) an increase in the number of transactions for manufacturers d) a reduction in number of shipments from manufacturers

An increase in the number of transactions for manufacturers - A decrease in the number of transactions for retailers, a decrease in transportation costs, and a reduction in number of shipments from manufacturers are the natural result of reducing the complexity of transactions between manufacturers and customers. - Transportation costs will decrease as manufacturers ship to fewer distributors and retailers buy from fewer suppliers

Forecasts for products that are subject to promotional demand are most useful if they are based on: a) quantitative factors only b) qualitative factors only c) both quantitative and qualitative factors d) neither qualitative nor quantitative factors

Both quantitative and qualitative factors - a forecast should take both factors into consideration

Which of the following is an element of demand management? a) CRM b) Setting overall supply levels c) RCCP d) Master Scheduling

CRM - Forecasting, order management or servicing, and CRM are elements of demand management - Setting overall supply levels is conducted during S&OP, which is after demand managed has provided input - RCCP is a supply management element - Master Scheduling takes place after S&OP, which takes place after demand management has provided an input

A time fence policy does which of the following? a) Controls the amount of change that can occur during predefined areas of the planning horizon b) Controls supply planning information for production c) Avoids excess inventory through a dynamic process d) Monitors changes in supply and demand conditions

Controls the amount of change that can occur during predefined areas of the planning horizon - The time fence policy controls the amount of change that can occur within a predefined area of the planning horizon. - The time fence policy is designed to control the demand side of the MPS - Time fence policies control the amount of change permitted to a MPS, they are not maintained - Time fence policies control the amount of change permitted within predetermined zones of the MPS, not changes in supply and demand conditions

Which of the following components should be addressed by a world-class customer service strategy? a) Customer concerns b) Customer concerns and supplier concerns c) Customer concerns, employee concerns, and supplier concerns d) Customer concerns, employee concerns, shareholder concerns, and supplier concerns

Customer concerns, employee concerns, shareholder concerns, and supplier concerns

Cash-to-Cash Cycle = Number of days of inventory + days of account receivable - ________________

Days of Accounts Payable

Which of the following techniques is best suited to forecasting demand when the demand pattern shows seasonal and trend components? a) Time series analysis b) Historical analogy c) Decomposition d) Causal

Decomposition - Decomposition is a time series technique specifically suited to forecasting when demand shows seasonal and trend characteristics.

In an MTO manufacturing environment, a key management issue to consider is: a) determining finished goods inventory levels b) determining the lead time for customers by managing the size of the backlog c) selecting a level production method d) line balancing

Determining the lead time for customers by managing the size of the backlog - Too large of a backlog = lengthened lead times - Too small of a backlog = concern that sufficient work does not exist - Finished goods inventory would be a key planning factor in an MTS environment - Selecting a level production strategy might be considered for a MTO company, but typically a chase method is the production choice - Line balancing is an execution technique for a repetitive or lean environment

Which of the following isa key element of customer relationship management? a) Setting filter limits at multiples of MAD b) Handling customer requests for changes to due dates outside the system c) Promising from on-hand inventory and future supply d) Differentiating the company's customer experience from rivals by superior anticipation and responsiveness

Differentiating the company's customer experience from rivals by superior anticipation and responsiveness - Setting filter limits is an element of demand filters, not customer relationship management. - Changes made by the customer for delivery must be entered into the system. - Promises from on-hand inventory and future supply are a characteristic of ATP

Tracking signals are computed by which of the following methods? a) Dividing the cumulative sum of errors by the MAD b) Dividing the average error by the trip value c) Multiplying the MAD by four d) Increasing the alpha coefficient to the MAD

Dividing the cumulative sum of errors by the MAD - the cumulative sum of errors is also referred to as the running sum of forecast error. - the trip value is a threshold predetermined by management - multiplying the MAD by four is one way to calculate the trip value - the alpha coefficient can be adjusted to place more emphasis on recent information but it is not used to compute the tracking signal

________________ measures the ability to handle a reduction in orders.

Downside supply chain adaptability

What manufacturing environment would best support the distribution channel attributes of low distribution intensity, high product variety, and low channel dependency? a) ATO b) MTS c) ATO / MTS d) ETO / MTO

ETO / MTO - ATO and MTS environments tend to require high distribution intensity, low product variety, and high channel dependency

Which of the following is the overall goal of a distribution system? a) Customer service b) Maximum distribution efficiency at lowest cost c) Minimum inventory investment and lowest-cost distribution d) Efficient, timely service with minimal inventory investment

Efficient, timely service with minimal inventory investment

Which of the following responses is a company most likely to consider when establishing the forecast for a new item being added to an MTS product line? a) Evaluate the sales promotion effect of the new item on sales of existing products b) Reduce the alpha factor so that downward-trending demand in recent periods is more heavily weighted c) Adopt pyramid forecasting in order to evaluate the importance of the new item above its family members d) Apply quantitative analysis techniques based on leading economic indicators to establish short-term forecasts

Evaluate the sales promotion effect of the new item on sales of existing products - If the new product is to replace an older product, it would be prudent to know what promotion of the older product caused a sales response. - Exponential smoothing techniques do not normally apply to new product introduction - Pyramid forecasting is a forecast aggregation and disaggregation process and it is not a method to emphasize certain products - Quantitative analysis typically is used when there is sales history -- leading economic indicators will predict the general direction of the entire industry for some period in the future but are not well-suited to individual product analysis

In a make-to-stock business, what level of the bill of materials do you master schedule?

Finished goods You will need a finish goods forecast to master schedule. COMPONENTS WOULD BE PLANNED BY MATERIALS REQUIREMENTS PLANNING

Return on supply chain fixed assets = (Supply chain revenue - COGS - Supply chain management costs) / ________________

Supply Chain fixed assets

The production forecast: a) is primarily used with master production scheduled items b) forecasts the family ATP multiplied by option percentages c) represents the product family forecast in two-level master scheduling d) is based on production lead times

Forecasts the family ATP multiplied by option percentages - The production forecast is used with two-level master scheduling and represents the ATP (MPS minus customer orders) at the family level multiplied by the option percentage. - The production forecast is sued with a subset of master-scheduled items only - The production forecast does not represent the product family forecast - The production forecast is not based on production lead times

In which of the following zones is it most difficult to respond to changes in customer demand? a) Danger b) Frozen c) Liquid d) Slushy

Frozen - The frozen sone should be the most protected in terms of the amount of change permitted - There is no zone called the danger zone - In the liquid zone extensive changes can be made without causing much disruption to the MPS - In the slushy zone some change is tolerated, but changes must be controlled carefully

All of the following are characteristics of customer service leadership EXCEPT: a) defining a vision of service excellence b) handling customer complaints c) being proactive with customers d) creating and maintaining high standards

Handling customer complaints - Leadership would not handle customer complaints themselves - Defining a vision of service excellence, being proactive with customers, and creating and maintain high standards are characteristics of customer service leadership

Which of the following quantitative techniques responds most quickly to trends? a) High-alpha-factor exponential smoothing b) Moving average c) Seasonal Index d) Expert opinion

High alpha-factor exponential smoothing - A low alpha-factor will react more slowly to a trend - The moving average does not respond well to trends - Seasonal index is not used for trend evaluation - Expert opinion is a qualitative technique

Which of the following qualitative methods of forecasting should a company consider for a product that is replacing another? a) Expert opinion b) Focus groups c) Historical analogy d) Panel consensus

Historical Analogy

S&OP fundamentals include which of the following? I. Supply and demand planning II. Disaggregating volume into a master schedule III. Product family planning IV. Mix planning a) I and III b) I and IV c) II and III d) III and IV

I and III - Disaggregating volume into a master schedule and mix planning are fundamental to master scheduling, not S&OP

Which of the following are possible solutions for a master scheduler trying to resolve a short-term problem with an overloaded critical work center? I. Schedule overtime or extra shifts II. Reduce the amount of subcontracting III. Establish committees to reduce setup times IV. Hire temporary help a) I and II only b) I and IV only c) II and III only d) II and IV only

I and IV only - Reducing subcontracting increases workload and therefore will not help an overload situation. - Establishing committees to look at reducing setup times will not help correct an overload in the short term.

During the S&OP process, performing a financial evaluation of alternative strategies includes which of the follow? I. Number and productivity of workers II. Cost of changing work levels III. Inventory costs IV. Priority sequence of the load a) II and III b) III only c) I, II, and III d) I, II, III, and IV

I, II, and III - Priority sequence of the load is determined at the execution level of MPC and not during the S&OP process

In master scheduling, hedging refers to a practice that: I. Provides safety lead time II. Provides safety inventory in case option mixes are different from those forecast III. provides safety capacity to protect against work center overload IV. provides safety inventory in case volume is greater than forecast a) III only b) I and III only c) II and IV only d) I, II, and IV only

I, II, and IV only - Hedging is a quantity of stock to protect against uncertainty of demand. - Hedging has the dimensions of timing and amount. - The hedge can be either a mix hedge or a volume hedge. - Hedging is not related to safety capacity - Hedging does use safety lead times to protect against late deliveries it DOES NOT use safety capacity - Hedging does provide safety inventory in case volume or option mixes are greater than forecast

Which of the following are data required for the development of a realistic MPS? I. New product introduction schedule II. Sales forecasts III. Shipment history IV. Workforce constraints a) I, II, and III only b) I, II, and IV only c) I, III, and IV only d) I, II, III, and IV

I, II, and IV only - Shipment history does not necessarily reflect true historical demand

Tracking signals do which of the following? a) Identify causes of forecast errors b) Identify forecast bias c) Compute the appropriate trip value to be used in demand filtering d) Adjust forecasts when errors are reported

Identify forecast bias - Tracking signals indicate bias within the forecast when the RSFE exceeds MAD by at least three times. - Tracking signals indicate deviation from the forecasts but not the causes of the deviation - Management is responsible for computing the true value to be used, the tracking signal does not do this - Tracking signals do not adjust forecasts, they only report deviations from the forecast

What is the difference in the Delphi Method and Panel Consensus?

In the Delphi method the members are not able to collaborate but must give individual answers. A panel consensus has to the ability to talk and come up with a pun intended consensus.

The MPS typically displays the plan for which of the following? a) Dependent demand items b) Product families c) Individual products d) Product components

Individual products - The MPS represents what the company plans to produce expressed in specific configurations, quantities, and dates. - MPS contains independent items - Product families are planned at the S&OP level - MPS schedules end items

Which of the following is not a valuable forecast evaluation activity? a) Tracking actual demand against projected demand b) Using standard deviation to track variation c) Determining and eliminating bias in a forecast d) Involvement of users in the process of developing forecast tools

Involvement of users in the process of developing forecast tools - Involvement of users ensures that they can effectively use the data from a forecasting system, but it is not an evaluation activity like all the others.

Which production planning method usually creates a build-up of inventory? a) Seasonal b) Level c) Chase d) Subcontracting

Level - The chase method does not build up inventory - Seasonal and subcontracting is a production planning method

In which of the following zones can change be made with relative ease? a) Danger b) Frozen c) Liquid d) Slushy

Liquid - In the liquid zone, extensive changes can be made without causing much disruption to the MPS - The frozen zone should be the most protected in terms of the amount of change permitted - Changes in the slushy zone must be reviewed for potential impact on existing supply and demand situations

Which of the following descriptions of the decoupling point does not apply in all manufacturing environments? a) Where inventory is placed to create independence between processes or entities b) Location of subassemblies awaiting final assembly c) Latest point in the supply process at which a supplier holds inventory in expectation of a customer order d) Strategic decision that determines customer lead time and inventory investment

Location of subassemblies awaiting final assembly - Describes the decoupling point in an ATO manufacturing environment -- all other answers apply to all manufacturing environments

Which of the following provides detailed supply and demand information for individual items and supports both purchased and manufactured products in all manufacturing strategies? a) S&OP b) MPS c) Capacity planning d) Marketing planning

MPS

What is the logical connecting point between the supply system and the distribution system? a) ISO 9000 b) MPS c) TOC d) MRP

MPS - MPS connects the distribution system, DRP, with the production system, MRP. - ISO 9000 is a documentation process related to documentation of production, return, and service policies and practices - TOC is the theory of constraints, an internal philosophy related to increasing throughput at bottlenecks in the production and delivery process - MRP receives input from the MPS and explodes the required bills of material to order purchased and production items

When defining product families, which of the following is most important? a) How the product is made b) Package size c) Market strategy d) Product load profile

Market strategy - product families are ideally based on both how the product is made and market strategy but if there is no alignment between the two, then the dominant choice is market strategy - product load profiles and package size do not influence the determination of product families

Which of the following is the process of creating a detailed statement of independent demand that is used to develop detailed material and capacity plans? a) Master scheduling b) Master planning of resources c) Rough-cut capacity planning d) Bill of material

Master Scheduling - Master planning of resources deals with S&OP, demand management, and master scheduling - Rough-cut Capacity planning is used to evaluate the feasibility of the master schedule - Bill of materials is a way to explode master schedule requirements into demand for specific material components

RCCP takes place at which of the following planning levels? a) Strategic Planning b) Business Planning c) Master Scheduling d) MRP

Master Scheduling - RCCP is used to determine if sufficient capacity is available for the MPS. - Resource Planning is used for Strategic and Business planning - CRP is used for material requirements planning

"The average of the absolute values of the deviations from some expected value" best defines which of the following terms? a) Standard deviation b) Forecast error c) Mean average deviation d) Mean absolute deviation

Mean Absolute Deviation - MAD averages the absolute values of deviations from expected values. - Standard deviation is a statistical measure of difference between a measure and the mean or average of all deviations. - Forecast error is the difference between the actual demand and the forecast demand - Mean average deviation is an inaccurate use of the acronym MAD

You are given the following tracking signals for three forecast methods you are thinking you want to use for your data. Number 1 = 2, Number 2 = -.5, Number 3 = .1. Which of statistically would be the best forecast method to use on your next forecast?

Number 3; 0.1 on the number line is closer to zero

"Responding to the customer with the price and availability, promise and confirmation, and advance ship notices" best defines which of the following terms? a) Focus on quality b) Continuous improvement c) Order fulfillment cycle d) Order qualifier

Order fulfillment cycle - The order fulfillment process is defined as a series of customer interactions with an organization through the order filling process, which includes price and availability, promise and confirmation, and advance shipping information

Which of the following can be considered a customer service measurement? a) Throughput percentage b) Order fill percentage c) Percentage of orders completely satisfied d) Inventory turns

Percentage of orders completely satisfied - Throughput percentage and order fill percentage are warehouse operations measurements. - Inventory turns is an inventory management measurement

Which of the following is most directly affected by forecast inaccuracy? a) Establishment of the firm planning time fence in the master schedule b) Safety stock levels of dependent demand items included in the forecast c) Leading indicators included in the extrinsic factors to determine the forecast d) Planned finished goods inventory level in an MTS environment

Planned finished goods inventory level in an MTS environment - planned finished goods inventory level in an MTS environment will cause levels to fluctuate based on degree and direction of inaccuracy

Which of the following is a point in the master scheduling process planning horizon that marks a boundary inside of which changes to the schedule may affect component schedules, capacity plans, customer deliveries, and cost? a) Demand time fence b) Projected available balance c) Planning time fence d) Available-to-Promise

Planning time fence - Changes inside the demand time fence are almost certain to have adverse effects in a well-planned process

The S&OP Process occurs at which of the follow levels? a) Individual Item b) Subcomponent line items c) Product families d) Service parts

Product Families

S&OP typically is done at which of the following levels? a) End item b) Stock keeping units c) Product family d) Component options

Product family - End items or stock keeping units generally are planned at the master scheduling level - Component options are planned at the material planning level of MPC

Which of the following best represents inputs to the master scheduling process? a) MPS, forecast, RCCP b) MPS, production plan, resource planning c) S&OP, MRP, capacity planning d) Production plan, forecast, distribution planning

Production plan, forecast, distribution planning - MPS is the output of the master scheduling process - Resource planning is used in the S&OP process - MRP is driven by the master scheduling process

The low cost strategy would ask you to use which method of managing your distribution inventory - Pull or Push?

Push - centrally controlling the inventory and allocating it out

In which of the following processes are qualitative techniques appropriately used? a) Determination of a seasonal index b) Pyramid forecasting c) Detection of a demand increase or decrease d) Extrapolation of essentially level data

Pyramid Forecasting - At the conclusion of the roll-up process, a qualitative decision can be made before forcing the result down. - Seasonal indexing, demand increasing and or decreasing, and extrapolation are all quantitative techniques

Which of the following is defined as the process of converting the MPS into the load for critical resources? a) ATP b) Resource capacity planning c) RCCP d) Multilevel master scheduling

RCCP - RCCP is the validity check for MPS - ATP is the uncommitted portion of a company's inventory and planned production, maintained in the MPS to support customer order promising - Resource capacity planning is used to determine the load placed on resources by product families in the production plan - Multilevel master scheduling is a master scheduling technique that enables any level in an end item's BOM to be master-scheduled

The supply chain council's metric for ___________ is the perfect order.

Reliability

Perfect order fulfillment is used to measure which of the following categories? a) Reliability b) Cost c) Responsiveness d) Flexibility

Reliability - Perfect order fulfillment is the metric used to measure the reliability, or dependability and quality, category. - Total supply chain management cost is used to measure cost - Order fulfillment cycle time measures responsiveness - Upside supply chain flexibility is used to measure flexibility

Seasonality is demand that shows which of the following patterns? a) Repetitive pattern over some time interval b) General movement up or down over time c) Repetitive pattern based on economic conditions d) Repetitive pattern based on promotional activity

Repetitive pattern over some time interval - General movement up and down over time = trend - repetitive pattern based on economic conditions = economic cycle

The process used to validate that adequate resources and capacity exist for the S&OP production plan is: a) bill of resources b) rough-cut capacity planning c) resource planning d) capacity requirements planning

Resource Planning -Resource planning is the process that evaluates the availability of key resources and the feasibility of the production plan generated by the sales and operations plan. - A bill of resources determines the amount of key resources used in the manufacturing process to produce a product and is a necessary input to the resource planning process - Rough-cut Capacity planning is the process used by master scheduling to validate that capacity is adequate - Capacity requirements planning is the process that validates the adequacy of capacity to execute the material plan

Order fulfillment life cycle is the sole level 1 metric for _________.

Responsiveness

Which of the following processes sets the projected backlog level at the product family level? a) Master Scheduling b) S&OP c) Business Planning d) Demand management

S&OP - During S&OP, the overall supply levels are set, the inventory level is planned, and the projected backlog level is planned at the product family level within defined supply constraints - S&OP takes place BEFORE master scheduling, AFTER business planning, and AFTER demand management provides input

Which of the following is an activity included in MPR? a) Business Planning b) Strategic Planning c) S&OP d) MRP

S&OP - S&OP, demand management, and master scheduling are activities included in MPR - Business Planning & Strategic Planning take place before MPR begins. - MRP is performed at a lower level

Distribution planning plans logistics capacity at the product family and end-item level at which of the follow planning levels? a) Strategic planning and MRP b) Business planning and MRP c) Master scheduling and MRP d) S&OP and master scheduling

S&OP and Master Scheduling - Strategic planning and MRP are all too early and too late to plan distribution logistics at the product family or end-item level

CRM segments customers into the following: profitability, strategic importance to the business, and ________________.

Special needs

Which of the following is part of a business plan? a) Statement of profit objectives b) Production Plan c) Short-term sales objectives d) Master Scheduling

Statement of project objectives - Statement of project objectives, a long-range strategy, and revenue and cost objectives are part of a business plan. - Business plan is concerned with long-range strategy and revenue and cost and profit objectives

Which of the following includes an analysis of the nature of the firm, the market, and the business environment? a) S&OP b) Benchmarking c) Product family analysis d) Strategic Plan

Strategic Plan - Benchmarking does not include analysis of the nature of the firm, the market, or the business environment -- it is apart of the business plan - Product family analysis is a part of the S&OP

Which team has the responsibility for preparing the preliminary production plan? a) Demand planning team b) Supply planning team c) Pre-S&OP team d) Executive S&OP team

Supply Planning Team - The supply planning team is responsible for preparing the production plan and recommending changes as necessary to meet the demand plan - The demand planning team reviews the sales plan - The pre-S&OP team makes decisions on balancing supply and demand - The executive S&OP team reviews and makes the final decisions on sales and operations plans as necessary

Master Scheduling is a balancing act between which of the following? a) Forecasts and orders b) Inventory and customer service c) Supply and demand d) Forecast and inventory

Supply and Demand - It is the master scheduler's job to find creative ways to balance supply and demand

Supply Chain costs = COGS + ________________

Supply chain management costs

What is the difference between an FAS and a MPS? a) The FAS addresses a longer-term planning period than the MPS and looks at customer orders rather than forecasted demand b) The FAS addresses a shorter-term planning period than the MPS and looks at customer orders rather than forecasted demand c) The FAS addresses a longer-term planning period than the MPS and looks at forecasted orders rather than customer needs d) The FAS addresses a shorter-term planning period than the MPS and looks at forecasted demand rather than customer orders

The FAS addresses a shorter-term planning period than the MPS and looks at customer orders rather than forecasted demand

In an assemble-to-order business, what level of the bill of materials do you master schedule?

The subassembly level -- you manufacture them up to a certain level that are stocked

Which of the following is the general rule for planning horizon? a) They depend on the delivery time and quantity of goods already ordered and in transit b) They extend into the future to cover the lead times through supply processes and delivery to the final distribution point c) They are primarily based on lead time in the manufacturing processes d) They are based on the gross requirement of each distribution center in the system for that item.

They extend into the future to cover the lead times through supply processes and delivery to the final distribution point

Which of the following best expresses the intent of forecasting? a) To give managers information on which to base decisions b) To give managers accurate data projecting material requirements c) To give shop floor workers ranges and variations within which production must take place d) To give production supervisors direct input into the distribution requirements system

To give managers information on which to base decisions - Forecasting gives managers information they can use to base their decisions on when lead times and other production complexities require production to precede actual orders. - Forecasts are seen as an estimate or approximation rather than accurate - Forecasts are generally not for the direct use of shop floor workers and do not dictate production demands - Production supervisors have no involvement with the distribution system

You are evaluating a forecast method and the tracking signal is - 5. Is this method statistically correct or should you explore something else?

Tracking signals must be between -4 and 4 to be statistically correct. This one is not, so choose another method of forecasting

________________ refers to the percentage increase in production that can be achieved and sustained in 30 days.

Upside Supply Chain Adaptability

________________ is measured by the number of days required to meet an unplanned and sustainable increase of 20% in delivery quantities to meet market demand.

Upside Supply Chain Flexibility

Statistical forecasting provides the best solution in which of the following situations in an MTS environment? a) When sales volume is low and forecast variance is low b) When sales volume is high and forecast variance is low c) When sales volume is low and forecast variance is high d) When sales volume is high and forecast variance is high

When sales volume is high and forecast variance is low - Statistical forecasting can be used when volume is low, the benefit of the forecast is not as great so the company should think of a MTO strategy - Make to Order works best with low value and high variance - Statistical forecasting only works for high volume and high variance when forecasting is at the aggregate level and when it is an ATO environment

Safety stock is also referred to as ________________ inventory.

buffer inventory

The tracking signal is computed by which of the following methods: a) cumulative sum of error / mean absolute deviation b) 4 times the mean absolute deviation c) period error / actual demand d) mean absolute deviation / standard deviation

cumulative sum of error / mean absolute deviation