Exam 2 Study Guide
Describe an Xbar and R chart and where it applies. Calculate upper and lower limits.
When variable measurement is used we use these two charts because normal distribution is assumed and has 2 parameters, mean (xbar) and variance (or range) (R) Xbar chart: a quality control chart that monitors the *mean* performance of a process R Chart: a quality control chart that monitors the *range* (variability) of a process
What does Poka-yoka mean?
(mistake-proofing) - a process or product that is designed so it is impossible for humans to make mistakes or for mistakes to be easily detected by humans when they do occur
Desribe ISO 9000 - what is it and why does it exist? What does ISO require for certification?
- one of the major approaches that companies are using to ensure quality today -It is oriented toward compliance, or what we have termed conformance quality - Only processes are measured, the product is not -it does not provide a complete quality system. The ISO 9000 standards specify that a company must have a quality system in place, including procedures, policies, and training, to provide quality that consistently meets customer requirements. A quality manual and careful record keeping are usually required as part of the documentation. Requires that the company have process flowcharts, operator instructions, inspection and testing methods, job descriptions, organization charts, measures of customer satisfaction, and continuous improvement processes. Employees must be trained in the procedures and actually follow them in practice.
What are the main things to htink about when defining quality?
-Quality is defined here as "meeting, or exceeding, customer requirements now and in the future." -Fitness for use (the benefits received by the customer and to the customer's satisfaction) -Consumer Satisfaction -Quality is not just defined based on the product or the service itself
What elements are special to the definition of service quality?
-Tangibles -Reliability -Responsiveness -Assurance -Empathy
What should drive the act of planning for quality?
-The customer needs are determined, usually through the marketing function. -these needs are either expressed directly by the customer or discovered through a process of market research
How is unit cost calculated?
Assume a chef gets paid $15 per hour, the assistant gets paid $11 per hour, and overhead cost is 50 percent of direct labor cost. At 60 percent of capacity, the average flow rate is six pizzas per hour. The cost per hour of operations is $15+$11=$26 for labor plus 50 percent added for overhead =$39 per hour, or $39/6=$6.50 per pizza. Assume the cost of ingredients is $2.00 per pizza. Therefore, the total cost is $6.50+$2.00=$8.50 per pizza.
Describe the cross-functional value of thinking in terms of the horizontal organization.
The process view of a business is horizontal in nature while the functional view is vertical. A business can be viewed as a system that consists of a collection of interconnected processes. Viewing a business as a collection of processes emphasizes the cross-functional nature of decision making. It illustrates that functions must make handoffs to one another in executing a process. As a result, time and information can be lost between processes. In some cases, the number of steps in a process is so large that the system cannot function in an efficient and effective manner.
What's the difference between planning and forecasting?
forecasting is what we think *will* happen in the future planing is what we think *should* happen in the future
What does a positive bias mean when considering a forecast method's accuracy?
if the bias is positive, it means that the starting point is too low and the forecasting method should be reset with a higher starting point
Define what is meant by Lean thinking and compare/contrast the Lean and JIT philosophies.
lean thinking is the concepts, principles, and techniques underlying lean production With JIT, instead of transforming the entire system, JIT manufacturing focused primarily on inventory reduction but ignored other aspects of waste reduction that was implemented in the Toyota Production System (TPS). Lean production philosophies say that by eliminating waste in all production processes by providing exactly what the customer needs and no more, they can create the best plants with the best labor productivity and quality while maintaining reduced defects and inventory.
What's meant by process thinking?
process thinking is the point of view that all work can be seen as a process it begins by describing the process of interest as a system defined by its boundaries, inputs, outputs, suppliers, custoemrs, and system flows
Can you calculate the various forecast errors using tables as shown in the text?
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Describe management's next concern once a process is under control.
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What must be considered in setting the alpha size?
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What must be considered in setting the moving average length?
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When is simple exponential smoothing the appropriate choice?
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What is a run chart? What kinds of data patterns indicate special cause interference (on a run chart)? What does a histogram add to the analysis of quality?
A run chart is a single line plotting some value over time it can help you see upward and downward trends and can show you a general picture of a process data patterns that indicate special cause interference: -shifts -trends -patterns Comparison of the shape of the distribution of the histogram to the specification limits can tell us whether the process is capable of meeting the required specification. If the tails are within the upper and lower specification limits then we are within the limits. The peak of the bar chart can also tell us if we are close to the nominal specification and allow us to make any necessary corrections.
Explain and discuss the Lean philosophy, with emphasis on how this philosophy challenges traditional approaches to manufacturing and service delivery.
After World War II the U.S. system of mass production was the envy of the world. Mass production—the production of standardized discrete products in high volume by means of repetitive manufacturing technologies—was the norm. Materials were produced in large batches, and machines were made to run faster to reduce costs. In some cases this resulted in sacrificing quality in the name of efficiency and creating narrow jobs that led to worker dissatisfaction, but still the world bought products manufactured in the United States. Lean production was defined as systematically eliminating waste in all production processes by providing exactly what the customer needs and no more. Tenets of lean thinking: 1.The first tenet in lean thinking is to specify precisely what about a product or service creates value from the customer's perspective.Value is not what the firm says but what the customer says. Value is often a solution to a problem a customer is facing that the customer is willing to pay for. Value, as such, is dynamic in nature and changes over time. Firms should design and deliver product and service features that customers value and stop doing activities that are not valued by customers (unless required for other reasons, for example, legal). 2. The second tenet in lean thinking is to identify, study, and improve the value stream of the process for each product or service.A typical value stream thus can include both value-added and non-value-added processing steps and tasks. The goal in studying the value stream is to eliminate the non-value-adding processing steps and tasks. 3. The third tenet in lean thinking is to ensure that flow within a process is simple, smooth, and error-free, thereby avoiding waste. 4. The fourth tenet in lean thinking is to produce only what is pulled by the customer. Complying with this tenet requires replacing the push system typical in traditional mass production with the pull system of lean production. A push system aims to produce goods or ensure delivery of services well in advance of demand, often according to a schedule or plan created from potentially inaccurate forecasts. Large batches of materials are pushed from one process or machine to the next regardless of whether the inventory is needed. This allows machines and processes to be utilized at full capacity, and inventory is considered a valuable asset. A pull system, on the contrary, waits for the process customer to signal a need for a good or service before producing it to fulfill that need. The signal from the customer is then sent visually up the various stages of production—and even the supply chain—to signal what and when production and delivery are needed. No upstream process is authorized to produce a good or service until a downstream customer asks for it, thus minimizing inventory throughout the production system. 5. The fifth tenet in lean thinking is to strive for perfection. Striving for perfection requires continuous improvement of all processes as well as radical redesign when necessary.The definition of perfection used here is an affordable good or service, delivered rapidly and on time, that meets the needs of the customer. When customer needs change, the definition of value changes and so does the definition of what constitutes perfection. There is therefore no end to the improvements that can be sought and made.
Analyze a control chart using the questioning process (from the handout).
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Describe the differences between the p-chart, the xbar and r chart, and the I-MR chart.
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What drives the success of quality management programs? Failure?
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Describe the first stage of step in bringing a process under control.
1) identify the critical points in each of the processes where inspection and testing are needed. do this by: -ensure that incoming raw materials or purchased services will meet specifications. (supplier certification) -test work in process or the service while it is being delivered -inspection of the finished product or service it is better to prevent defects from occurring than to inspect and correct defects after production 2) Decide on the type of measurement to be used at each inspection points. 2 types: Variables measurement (length, height, weight) and attribute measurement (discrete scale by counting the # of defective items or # of defects per unit) 3) Decide on the amount of inspection to use 4) Decide who should do the inspection
Describe the two mistakes managers can make when looking at an individual data point without the benefit of control chart limits.
1. Assume a process is in control when it's actually out of control 2. Assume a process is out of control when it's actually in control
What are the main measures of forecast error and how do they differ?
1. Cumulative sum of forecast errors (CFE): bias in the forecast; bias will be zero, ideally 2. Mean square error (MSE): measure the variance in the forecast error; sqrt of MSE is the well-known SD and they use it so that (+) and (-) errors don't cancel each other out 3. Mean absolute deviation of forecast errors (MAD): measures the variance in the forecast error; computed from absolute value instead of sqrt; easy to understand and use 4. Mean absolute percentage errors (MAPE): normalizes the error calculations by computing a % error; makes it possible to compare forecast errors for different time-series data *formulas on formula sheet in respective order*
Why do 70% of BPR projects turn out less than successful?
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What are the seven tools of quality control? How should control limits and specification limits relate in a capable process?
1. Flowcharts --> purpose: understanding the process and identifying possible problem areas 2. Check sheets --> purpose: tabulating data on the problem area 3. Histograms --> purpose: Illustrating the frequency of occurrence of measures 4. Pareto diagram --> purpose: Identifying the most important problems 5. Cause-and-Effect diagrams --> purpose: showing possible causes of the problem 6. Scatter diagrams --> purpose: investigating causes and effects 7. Control charts --> purpose: holding the gains from process improvement DON'T KNOW SECOND PART
What are the main steps of process flowchart analysis?
1. Identify and select a relevant transformation process (or system) to study. 2. Identify an individual or team of individuals to be responsible for developing the flowchart and, ideally, for subsequent analyses 3. Specify the boundaries of the transformation process 4. Identify and sequence the operational steps or activities necessary to complete the output for the customer(s) 5. Identify the performance metrics for the operational steps or the activities within the selected transformation process 6. Draw the flowchart, defining and using symbols in a consistent matter
What are the principles of BPR?
1. Organize around outcomes, not tasks 2. Have the people who do the work process their own information 3. Put the decision point where the work is performed, and build control into the process 4. Eliminate unnecessary steps in the process
Discuss alternative positions an organization might take when deciding on the timing of facilities investments.
1. Preempt the competition: firm leads by building capacity in advance of the needs of the market. Provides a positive capacity cushion and may stimulate the market while at the same time preventing competition from coming in for a while. OR 2. Wait and See: firm waits to add capacity until demand develops and the need for more is clear. Company lags market demand (lower risk)
Discuss facilities strategy in terms of the choices an organization has for focusing its facilities in different ways, including the advantages and examples of different focal points.
1. Product-focused: produce 1 family or type of product or service, usually for a large market. Used when transportation costs are low or economies of scale are high 2. Market-focused: located in the markets they serve. Many services facilities fall into this category because they cannot be transported. International facilities tend to be market focused because of tariffs, trade barriers, and potential currency fluctuations 3. Process-focused: 1 technology or at most 2. Frequently produce components or subassemblies that are supplied to other facilities for further processing 4. General-purpose: produce several types of products and services, using several different processes. Great deal of flexibility.
Compare and contrast the common variables available for modifying supply in an aggregate planning context, including the associated costs of these variables.
1. hiring and laying off workers. 2. using overtime and undertime. 3. using part and temporary labor. 4. carrying inventory. 5. subcontracting (outsourcing of work). 6. co-operative agreements.
All forecasts should contain what 2 numbers?
1. the best estimate of demand (mean, median, mode) 2. the best estimate of forecasting error (SD, absolute deviation, or range)
What did Deming contribute to the field?
14 management principles 1) Create constancy of purpose toward improvement of products and services with the aim of being competitive and staying in business for long-run, rather than short-run, profits 2) Adopt the new philosophy by refusing to allow commonly accepted levels of mistakes, defects, delays, and errors. Accept the need for change. 3) Cease dependence on mass inspection. Rely instead on building quality into the product in the first place and on statistical means for controlling and improving quality 4) End the practice of awarding business on the basis of price tag alone. Instead, minimize total cost. Reduce the # of suppliers by eliminating those who cannot provide evidence of statistical control of processes 5) Improve constantly, and forever, systems of production to improve quality and productivity and thus constantly reduce costs 6) Institute training and retraining for all employees 7) focus management and supervisors on leadership o their employees to help them do a better job 8) Drive out fear. Don't blame employees for "systems problems." Encourage effective two-way communications. Eliminate management by control. 9) Break down barriers between departments. Encourage teamwork among different areas such as research, design, manufacturing, and sales. 10) Eliminate programs, exhortations, and slogans that ask for new levels of productivity without providing better methods 11) Eliminate arbitrary quotas, work standards, and objectives that interfere with quality. Instead, substitute leadership and continuous improvement of work processes. 12) Remove barriers (poor systems and poor management) that rob people of pride in their work 13) Encourage lifelong education and self-improvement of all employees 14) Put everyone to work on implementing these 14 points. -an advocate of statistical process control -emphasis on continuous improvement -PDCA wheel (plan, do, act, check)
Compare and contrast the common methods for modifying demand to fit capacity.
4 methods: 1. Pricing: differential pricing to adjust demand. (matinees, off-season pricing) 2. Ads and promotion: stimulate demand. timed to promote slack periods. 3. Backlogs and reservations: demand can be hurt by asking customers to wait. shifts from peak to slack capacity. 4) Development of complementary offerings: seasonal demands have counter-cyclical trends
Describe the categories within the Cost of Quality (AKA: cost of poor quality).
Categories: prevention, appraisal, internal failure, and external failure - a reduction in the cost of quality can lead to a significant improvement in profit. - Control costs (related to activities that remove defects from the production stream): 1. Prevention Costs (such as quality planning, new product reviews) 2. Appraisal Costs (eliminating defects after they occur, but before delivered to the customers) - Failure costs: 1. Internal failure (during the production process; includes scrap, rework, quality downgrading, and machine downtime) 2. External failure (after product shipping; warranty charges, returned goods, and allowances)
Explain the targeted Cp and Cpk values.
Cp: -If the process is centered within the specification range, Cp is greater than or equal to 1 will be a good indicator of the ability of the process to meet its specifications, since the process width will be within the specification width -If the process is centered in the specification range and Cp=1, the process is considered to be minimally capable of meeting the specifications -a process with cp less than 1 must be imporved by reducing the SD or increasing the specification width, if possible, to become capable. Cpk: ??
What is the main lesson from Deming's famous red bead experiment?
Dr. Deming used the Red Bead Experiment to clearly and dramatically illustrate several points about poor management practices. This includes the fallacy of rating people and ranking them in order of performance for next year, based on previous performance. The Red Bead Experiment uses statistical theory to show that even though a "willing worker" wants to do a good job, their success is directly tied to and limited by the nature of the system they are working within. Real and sustainable improvement on the part of the willing worker is achieved only when management is able to improve the system.
Describe what is meant by good facilities strategic planning, with emphasis on the questions that must be answered, the factors that commonly influence facilities strategy, and recommendations for how management should approach this task.
Facilities strategy considers the amount of capacity, the size of facilities, the timing of capacity changes, facilities locations, and the types of facilities needed for the long run. It must be coordinated with other function areas due to the necessary investments (finance), market sizes that determine the amount of capacity needed (mktg) workforce issues related to staffing new facilities (HR), estimating costs in new facilities (accounting), and technology decisions regarding equipment investments (engineering). Affected by the following factors: 1. Predicted demand 2. Cost of facilities 3. Likely behavior of competitors 4. Business strategy 5. International considerations ??
How is process flow rate calculated?
Flow rate = minimum(supply, demand, capacity) In the factory example above, assume that capacity was 200 units per day, demand was 75 units per day, and supply was 100 units per day. The flow rate would be 75 units per day (the minimum of the three variables) assuming they can produce only what is demanded. If they were able to increase demand to 150 units per day, the flow rate would be only 100 units per day unless supply also could be increased.
Describe the primary dimensions of quality and what they mean.
For manufacturing -Quality of design: determined before a product is produced. This determination is usually the primary responsibility of a cross-functional product design team -Quality of conformance: producing a product to meet the specifications. When the product conforms to specifications, operations considers it a quality product regardless of the quality of the design specifications -the "abilities" 1. Availability: continuity of service to customer. Availability=Uptime/(Uptime+Downtime) Availability = MTBF/(MTBF+MTTR) 2. Reliability: the length of time a product can be used before it fails. 3. MTBF: Mean time between failures 4. Maintainability: restoration of a product or service once it as failed. 5. MTTR: Mean time to repair
Describe what's meant by Six-Sigma quality
Improves the quality of process by identifying and removing the causes of defects (errors) and minimizing variability in manufacturing and business processes. It uses a set of quality management methods, including statistical methods, and creates a special infrastructure of people within the organization (champions, black belts, green belts, yellow belts. ect.) who are experts in these methods.
What did Crosby mean by "quality is free"?
Phillip Crosby talked about the 14 step quality implementation program, emphasized on "conformance" in his definition of quality, and believed in making zero defects. If you don't put the defects in, then you don't have to pay to find the defects and then remove them. Hence, there will be no extra cost meaning that quality is FREE!
Explain what is meant by physical control in a Lean system and discuss the main ways an organization might go about increasing this control.
Increased control can be had through: A kanban system is used to pull parts through the production system to meet the master schedule. A fixed number of containers is provided for each part, thus limiting the amount of work-in-process inventory. The pull system can also be applied in service operations by providing only what is needed when it is needed by the customer. New supplier relationships must be established to make lean production successful. Frequent deliveries and reliable quality are required. Often, long-term single-source contracts will be negotiated with suppliers.
What is the Delphi technique and when is it appropriate?
It's a panel of experts who anonymously answer a series of questions. The data is then compiled, analyzed, and shared back to the experts - including reasons given to explain responses. Experts then revise their responses based on the new information. This question-answer-feedback process is repeated until a consensus is reached. When to use: long-range sales forecasts for capacity or facility planning and for technological forecasting to assess when technological changes might occur
Discuss waste in operations, including its definition relative to Lean and JIT and how waste is viewed from a value-analysis perspective.
Lean Thinking: Waste, in lean thinking, is anything that does not contribute value to the product or service being produced and delivered to the customer; rather than adding value, waste adds costs. The Japanese term for waste is muda. In many manufacturing, administrative, and service processes only 5 to 10 percent of total throughput time adds value for the customer. Firms want to eliminate obvious waste, but many forms of waste are hidden. For example, the value-added time to produce a product may be only three hours, but it takes a week to complete it. The muda or non-value adding time might include waiting for machines or labor to become available, dealing with backlogs, searching for materials, or correcting processing errors. 7 forms of waste: • Overproduction: Producing more than the demand of customers, resulting in unnecessary inventory, handling, paperwork, and warehouse space. • Waiting time: Operators and machines waiting for parts or work to arrive from suppliers or other operations; customers waiting in line. • Unnecessary transportation: Double or triple movement of materials due to poor layouts, lack of coordination, and poor workplace organization. • Excess processing: Poor design or inadequate maintenance of processes, requiring additional labor or machine time. • Too much inventory: Excess inventory due to large lot sizes, obsolete items, poor forecasts, or improper production planning. • Unnecessary motion: Wasted movements of people or extra walking to get materials. • Defects: Use of material, labor, and capacity for production of defects, sorting out bad parts, or warranty costs with customers. Just in Time manufacturing evolved into lean productions JIT: focused mostly on inventory reduction but ignored other aspects of waste reduction
Explain how Lean systems work - with emphasis on the keys to a successful system.
Lean production was defined as systematically eliminating waste in all production processes by providing exactly what the customer needs and no more. Keys to successful system: Stabilizing the master schedule --> level the amount of work that is performed each day Kanban control systems --> signal the need for more parts, never more than needed, uses cards and containers Lot sizes of one --> ideally, or many small lots in a mixed production schedule Minimal setup/changeover time Multifunction employees, flexible and cross-trained Low inventory --> visible, "right-sized storage" Insistence on Quality - "make it right the first time," defects found quickly and corrected Frequent supplier deliveries - requires partnership and proximity Takt time - producing at the rate of customer demand Group technology - work cells, as opposed to specialized work departments Objective of Lean: Increased ROI Reduced waste Reduced cost of poor quality Reduced inventory investment Increased customer satisfaction Increased revenues
Compare and contrast lean and six-sigma.
Lean: reduce waste (non-value-added activities); waste can include, in part, defects. Six Sigma: reduce defects as seen by customers. Objectives, organization, methods, types of project are different. Look table 9.5, p.207
What areas of a company typically use forecast information? For what kinds of decisions?
Marketing: planning products and services, promotion, and pricing Finance: as an input to financial planning Operations: an input for operations decisions on process design, capactiy planning, and inventory
Why is information-flow analysis important? What can be the result?
Measure the inputs: Materials, labor, energy, capital, etc. - units consumed. Also consider information as an input
Describe the implications of a Lean system on the employees, including the employee-related objectives for successful Lean system performance.
One of the critical elements needed to make a lean production system successful is multifunction workers, who have a much broader set of skills than their counterparts in traditional environments. Cross-training of workers is therefore a critical human resources responsibility. In most cases, each worker must be able to operate several machines in a manufacturing setting or perform a variety of tasks in a service setting. In manufacturing, since parts are not produced unless they are needed, the worker must be able to shut down one work center and move on to another work center where parts are needed. The worker also must be able to set up machines, do routine maintenance, and inspect the parts. Moving toward a flexible workforce may require changing the way workers are paid and rewarded. Traditional pay systems are often based on seniority and level of job skills. New pay systems in a lean system will reward workers on the basis of the number of different jobs they can perform. This will encourage workers to learn more skills and become more flexible.
Describe how to calculate a weighted moving average.
One way to make the moving average respond more rapidly to changes in demand is to place relatively more weight on recent demands than on earlier ones (called a *weighted moving average*) Ft+1 = At = (W1)(Dt) + (W2)(Dt-1) + ... + (Wn)(Dt-n+1)
Explain the difference between Cp and Cpk. Calculate Cp and Cpk given supplied process information.
Process capability index (Cp): the ratio of the specification (spec) width to the process width --> (spec width/process width) Cp measure requires the process to be centered in the specification rage for an accurate measure of process capability. Because of this problem, another more widely used measure (Cpk) has been devised. Cpk more accurately reflects the actual process capability and is the measure commonly used by industry. It overcomes the centering problem by calculating the process capability for each half of the normal distribution and then taking the minimum of the 2 calculations.
What's the purpose of process-flow analysis?
Process flow analysis is viewing and analyzing the transformation process as a sequence of steps connecting inputs to outputs it is used to discover better methods or procedures for producing and delivering a product or service deemed to be of value to customers.
Discuss the relationship between setup time and production batch size, especially the benefits of reducing both.
Reducing setup time is important in lean production systems because it increases available capacity, increases flexibility to meet schedule changes, and reduces inventory. As setup time approaches zero, the ideal lot size of one unit can be reached. Single setups are being sought in many companies. This refers to a setup time that is completed in single digit minutes. One-touch setups are also being pursued; this refers to a setup of less than one minute. These low setup times can be achieved by designing a two-step setup process. First, external and internal setups are separated. The term internal setup refers to actions that require the machine to be stopped, whereas an external setup can be done while the machine is operating. The external setup is analogous to the on-deck batter in baseball; the player is warmed up and ready to move into position as soon as the prior batter is finished. After internal and external setups are separated, as much of the setup as possible is converted from internal to external. When setup time cannot be reduced, it may not be possible or economical to achieve perfectly mixed production at final assembly. In such cases, small lots should be scheduled while continuing efforts to further reduce the lot size. The goal of single-unit production, a lot size of one, should not be abandoned since it may help to further reduce total system costs.
How does reengineering differ from process analysis?
Reengineering/BPR (business process reengineering): A radical change in the way an organization operates, involves a fundamental rethinking of a business system, usually includes eliminating non-value-added steps, automating some steps, changing organizational charts, and restructuring rewards systems - often includes job enlargement (reduces # of ques and gives customer a single point of contact - usually assoicated with downsizing. Process Analysis: Process-flow analysis takes the flowchart and the measurements of a transformation process and seeks answers to relevant questions. These questions help highlight opportunities that can be implemented to improve the transformation process.
What is rolled yield? What does this concept mean in terms of managing quality?
Rolled yield accounts for the cumulative defect rate observed by the final customer When a product is complex, it is important that the suppliers maintain very high levels of quality to ensure that the final product has the required quality. For example, suppose a product or service has 100 components or parts and each part has a yield of 99% (1% defective). Then the overall yield of the final product is obtained by multiplying the yields of all the individual producers. Since there are 100 producers wiht the same yield (.99), in this case the rolled yield is = (.99)^100 = 0.366
Why would a company use qualitative forecasting techniques?
Should be used when: -past data are not reliable indicators of future conditions -new product and new service introductions for which historical demand data are not available 4 methods: Delphi, market surveys, life-cycles analogy, and informed judgement
Explain the DMAIC framework.
Six Sigma is a systematic method for process improvement that often uses the five steps defined by the acronym DMAIC -Define: the process is selected for improvement, and the project charter is specified -Measure: Quality variables valued by the customer are measured, and goals are set for improvement. -Analyze: The root causes of the current defect levels are identified, and alternatives are considered for process changes. -Improve: the process is changed and checked for improvement -Control: this step ensures that the process improvement is not lost over time.
Describe the conventional symbols used in a flow-process chart.
Terminator (oval): shows the "start" and the "end" of the flowchart, thereby specifying the boundaries of the transformation process to study. START and END should be written inside the symbol for clarity Process (rectangle): denotes an operational step or an activity to be performed. A short description of the operational step or the activity should be written inside the symbol for clarity Decision/Evaluation (diamond): represents a decision, an evaluation, or an "IF-THEN" condition that has multiple potential outcomes (i.e., branches of arrows). The decision, evaluation, or condition should be properly described in writing inside the symbol for clarity. Each branch of arrow should be properly labeled to denote the meaning of the outcome from the decision, evaluation, or condition Flow (arrow): denotes the direction of flow within the flowchart; the flow could be that of materials, information, or person (e.g., customer)
Describe an Individuals and Moving Range (I-MR) chart and where it applies. Calculate upper and lower limits.
The individuals and moving range (I-MR) chart is one of the most commonly used control charts for continuous data; it is applicable when one data point is collected at each point in time. The I-MR control chart is actually two charts used in tandem. Together they monitor the process average as well as process variation. With x-axes that are time-based, the chart shows a history of the process.
How did Juran frame the management of quality?
Through his Quality Trilogy: planning, control, and improvement Planning: companies should identify the major business goals, customers, and products required. New products should be introduced only after they are carefully tested and when they meet a verified customer need. Much of quality improvement requires careful planning to ensure that the most important quality problems are attacked first - "the vital few". Control: control of quality through the use of the statistical methods. Management should institute the procedures and methods needed to ensure quality and then work to keep the system continuously in control. Improvement: break-through improvement and continuous improvement of processes. Training and involvement of all employees is necessary to ensure continuous quality improvement.
What's wrong with using inspectors to ensure good quality?
You should ensure good quality before the product is made - not after. Implement good quality ensurance during production - not after.
What does the Baldrige award consider? Where is the emphasis placed?
a framework for evaluating and implementing quality principles and concepts. Each year, the award is given to at most three organizations in each of 6 categories: manufacturing, service, small business, healthcare, education, and nonprofit. Categories that are considered: 1) Leadership 2) Strategic Planning 3) Customer Focus 4) Measurement, Analysis, and Knowledge Management 5) Workforce Focus 6) Process Management 7) Results Emphasis is placed on not requiring a particular dogma but allowing flexibility in defining "good quality management" by individual companies.
Describe a p-chart and where it applies. Calculate upper and lower limits using supplied data.
a quality control chart used to measure the proportion of units produced in a process that are defective; a unit is considered defective if any attribute of the unit does not conform to the standard UCL = p + 3sqrt([p(1-p)]/n) LCL = p - 3sqrt([p(1-p)]/n)
What's the simple idea behind exponential smoothing?
based on the simple idea that a new average can be computed from an old average along with the most recent observed demand At = aDt + (1 - a)At-1 where: At-1 is the old average, Dt is the demand just observed, and *a* the proportion of weight placed on the new demand versus the old average OR Ft+1 = Ft + a(Dt - Ft)
Why does BPR have a negative connotation attached to it?
because it is associated with downsizing
Define capacity cushion and discuss the main cushion-related strategies.
capacity cushion = 100% - Utilization (difference between the output that a firm could achieve and the real output that it produces to meet demand) 1) Large cushion: capacity is greater then demand by a wide margin. Appropriate when there is an expanding market or when the cost of building and operating capacity is inexpensive relative to the cost of running out of capacity. Enables firms to capture market share ahead of competitors. Helps meet unpredictable customer demand. Common when using a make-to-order process. 2) Moderate cushion: conservative. have a little wiggle room. Built to meet the average forecasted demand. Used when the cost of running out is about in balance with the cost of excess capacity. 3) Small cushion: zero buffer. max utilization. Appropriate when capacity is very expensive, relative to stockouts. Make-to-stock.
How is process capacity determined?
capacity is the maximum rate of output from a transformation process or the maximum flow rate that can be sustained over a period of time capacity = Minimum (capacity of resource 1, . . . ., capacity of resource n) Note that the capacity of the entire process cannot be larger than the capacity of the most constraining (the smallest capacity) resource, which is called the bottleneck.
What is distinctive about service blueprinting? What does it do?
service blueprinting is a process map for a service that includes moments of truth, line of visibility, fail points, and additional information needed to create the right customer experience The main idea is to get the customer's perspective into the service design and improvement process Moments of truth: all points of interaction between the customer and service providers. The line of visibility: separates a service operation into back-office operations that take place without the customer's presence and front office operations in direct contact with the customer. The service blueprint is more formal and structured and shows the interactions between processes, provides a conceptual model to study the service experience prior to implementing it and also makes the implementation easier.
What is Little's Law? What does it do for OM?
shows that the average number of items in a system (I) is the product of the average arrival rate to the system (R) and the average length of time an item stays in the system (throughput time) (T) I=TxR where: I = average # of things in the system (or inventory) T = average throughput time (processing time + waiting time R = average flow rate in the process
Construct a table to calculate forecasts using a moving average.
table 11.3 pg. 259 PRACTICE DRAWING EXAMPLE
How is process throughput time calculated?
throughput time is the time from when processing begins until the product or service is completely finished T = average throughput time(processing time + waiting time)
Describe the data pattern most suited to basic time-series forecasting methods.
time-series forecasting: used to make detailed analyses of past demand patterns over time and use those patterns to predict demand in the future data pattern most suited: moving average Moving Average: At = (Dt + Dt-1 + ... + Dt-N-1)/N table 11.3 on pg. 259 for example
Explain what is means when a process is in statistical control and draw and example of this situation.
to be in statistical control is when measurements are taken of quality attributes throughout the company and monitored over time. if these measurements have constant variance around a constant average, the system is stable.
