Quality Management and Six Sigma Flashcards

Question 1

What does quality management mean as an organizational discipline?

Accepted Answer

Quality management is a set of coordinated activities that direct and control an organization with respect to quality. It includes planning, quality assurance, quality control, and continuous improvement, all aimed at meeting customer requirements consistently. The goal is to prevent defects and build reliable processes rather than only inspecting finished products.

Question 2

Who is W. Edwards Deming and why is he associated with quality?

Accepted Answer

W. Edwards Deming was an American statistician and consultant who taught that quality comes from improving systems rather than blaming individual workers. He emphasized a cycle of planning, doing, checking, and acting. His ideas on variation and management strongly influenced Japanese industry and quality movements worldwide.

Question 3

What is the difference between quality assurance and quality control?

Accepted Answer

Quality assurance is process-focused and aims to prevent defects by ensuring that the processes used to make a product or deliver a service are sound and followed. Quality control is product-focused and detects defects by inspecting or testing outputs against specifications. Assurance builds confidence in the system, while control verifies the results it produces.

Question 4

What is the cost of poor quality and why do organizations track it?

Accepted Answer

The cost of poor quality is the total expense an organization incurs because products or services fail to meet requirements. It is grouped into prevention, appraisal, internal failure, and external failure costs. Organizations track it to show where money is lost and to justify investments that reduce defects, rework, warranty claims, and customer complaints.

Question 5

What does customer focus mean as a quality management principle?

Accepted Answer

Customer focus means that an organization understands current and future customer needs, meets their requirements, and works to exceed their expectations. It is a core principle because every other activity, from design to delivery, is judged by how well it serves customers. Measuring satisfaction and acting on feedback keep this focus practical.

Question 6

What is the role of top management in a quality system?

Accepted Answer

Top management sets the quality policy, defines clear objectives, and provides the people, funding, and authority needed to achieve them. Leaders demonstrate commitment by reviewing performance, removing obstacles, and modeling the behaviors they expect from staff. Without visible leadership involvement, quality initiatives tend to stall because employees follow what managers actually reward.

Question 7

What is continuous improvement and what is a common model for it?

Accepted Answer

Continuous improvement is an ongoing effort to make small, incremental gains in processes, products, and services over time. A common model is the Plan-Do-Check-Act cycle, in which a team plans a change, tests it on a small scale, checks the results against expectations, and acts to standardize successful changes or adjust failed ones.

Question 8

Why is quality management considered a system rather than a single tool?

Accepted Answer

Quality management is considered a system because its parts depend on one another and must work together. Policies, processes, measurements, people, and feedback loops form an interconnected whole, so a change in one area affects the others. Treating quality as a single tool usually addresses symptoms and leaves underlying causes in place.

Question 9

What is the purpose of a check sheet in data collection?

Accepted Answer

A check sheet is a structured form used to record how often specific events or defects occur during a defined period. Each occurrence is marked with a tally or checkmark in a predefined category, which makes data collection quick and consistent. They often feed Pareto charts and histograms.

Question 10

What is a Pareto chart and what principle does it rely on?

Accepted Answer

A Pareto chart is a bar chart that orders problem categories from most to least frequent. It relies on the Pareto principle, the observation that a small share of causes usually produces most of the effects. Teams use it to focus improvement efforts on the vital few issues instead of the trivial many.

Question 11

What is a histogram and what can it reveal about a process?

Accepted Answer

A histogram is a bar graph showing the frequency distribution of a measured variable, with the values grouped into intervals. It reveals the shape, center, and spread of the data, showing whether a process is centered on its target, how much it varies, and whether the distribution is skewed or has multiple peaks.

Question 12

What is a fishbone diagram used for in root cause analysis?

Accepted Answer

A fishbone diagram, also called an Ishikawa or cause-and-effect diagram, organizes possible causes of a problem into categories such as methods, machines, materials, people, measurements, and environment. The problem is written at the head, and branches list contributing causes. Teams use it in brainstorming to explore causes broadly before testing which ones are responsible.

Question 13

What does a control chart show and why is it useful?

Accepted Answer

A control chart plots process data over time against a center line and upper and lower control limits. It shows whether a process is stable, meaning its variation comes only from common causes, or unstable, meaning special causes are present. Operators can react to signals rather than adjusting a process that is performing normally.

Question 14

What is process mapping and what is a flowchart's purpose in it?

Accepted Answer

Process mapping is a visual representation of the steps, decisions, inputs, outputs, and handoffs in a process. A flowchart is the most common form, using standard symbols such as rectangles for activities and diamonds for decisions. Mapping the current state often reveals unnecessary steps, delays, and rework loops that were hidden before drawing.

Question 15

What is a SIPOC diagram and when is it used?

Accepted Answer

A SIPOC diagram is a high-level tool that lists suppliers, inputs, process steps, outputs, and customers for a process. It is typically used early in an improvement project, before detailed analysis begins, to define the scope and clarify who provides what and who receives the results.

Question 16

What is cycle time and why does it matter in process improvement?

Accepted Answer

Cycle time is the elapsed time from the start of one unit of work to its completion, often measured as the interval between successive outputs. It matters because long or variable cycle times delay customers and hide bottlenecks. Reducing cycle time often improves flow, responsiveness, and capacity without requiring additional resources.

Question 17

What is Six Sigma and what is its central goal?

Accepted Answer

Six Sigma is a data-driven methodology for improving processes by reducing variation and eliminating defects. Its central goal is to make processes so consistent that defects are extremely rare, which in its classic target means no more than about 3.4 defects per million opportunities. It combines statistical analysis with structured problem-solving and project management.

Question 18

What does the sigma level measure in Six Sigma?

Accepted Answer

The sigma level is a measure of how capable a process is of producing output within specification limits, expressed in standard deviations between the process mean and the nearest limit. Higher sigma levels mean fewer defects. Analysts often convert it to defects per million opportunities using a conversion table or formula.

Question 19

What is DPMO and how is it calculated?

Accepted Answer

DPMO stands for defects per million opportunities, a normalized measure of defect rate. It is calculated by dividing the number of defects by the total number of opportunities for defects and multiplying by one million. Because it adjusts for units with multiple possible defect points, DPMO allows fair comparison across different products and processes.

Question 20

What is DMAIC and what does each letter stand for?

Accepted Answer

DMAIC is the core structured improvement method for existing processes in Six Sigma. The letters stand for Define, Measure, Analyze, Improve, and Control. Define clarifies the problem and goals, Measure establishes baseline performance, Analyze identifies root causes, Improve tests and implements solutions, and Control sustains gains with monitoring and standard work.

Question 21

What is DMADV and when is it used instead of DMAIC?

Accepted Answer

DMADV is a Six Sigma method for designing new products, services, or processes, or redesigning them when existing processes cannot be improved enough. Its letters stand for Define, Measure, Analyze, Design, and Verify. It is used instead of DMAIC when no suitable process exists yet, so capability must be designed from the start.

Question 22

What is the purpose of the Define phase in DMAIC?

Accepted Answer

The Define phase establishes a clear problem statement, the project goals, the scope, and the customers affected. Teams often create a project charter and identify critical-to-quality requirements, which translate customer needs into measurable specifications. A well-defined project prevents wasted effort on symptoms that do not matter to customers or the business.

Question 23

What is the purpose of the Measure phase in DMAIC?

Accepted Answer

The Measure phase establishes a baseline by collecting reliable data on current process performance. Teams validate the measurement system, identify the key process input and output variables, and calculate current defect rates or process capability. This baseline provides the reference point for judging whether later changes truly improve the process.

Question 24

What is lean thinking and how does it relate to quality?

Accepted Answer

Lean thinking is a management approach focused on maximizing customer value while minimizing waste, such as waiting, overproduction, defects, and unnecessary motion. It relates to quality because defects are a form of waste, and building correct work at each step reduces the rework and inspection that consume resources.

Question 25

What is the difference between a mean and a median?

Accepted Answer

The mean is the arithmetic average, calculated by summing all values and dividing by the number of values. The median is the middle value when data are arranged in order. The mean is sensitive to extreme values, while the median resists their influence, so the median is preferred for skewed data.

Question 26

What is standard deviation and what does it tell you about data?

Accepted Answer

Standard deviation measures the distance of data points from the mean, expressing how spread out the values are in the original units. A small standard deviation indicates consistent results clustered near the average, while a large one signals greater variation. In Six Sigma, reducing standard deviation is central to making processes predictable and capable.

Question 27

What is a normal distribution and why is it important?

Accepted Answer

A normal distribution is a symmetric, bell-shaped probability distribution in which the mean, median, and mode coincide. Many natural and process measurements approximately follow it, and its known properties let analysts estimate how often values fall within certain ranges. Common Six Sigma calculations, including process capability and control limits, assume or approximate normality.

Question 28

What is a Z score and how is it used in Six Sigma?

Accepted Answer

A Z score expresses how many standard deviations a value lies above or below the mean. It standardizes measurements so that values from different scales can be compared. In Six Sigma, Z values are used to convert observed defect rates into sigma levels using normal distribution tables or software.

Question 29

What is a confidence interval and how should it be interpreted?

Accepted Answer

A confidence interval is a range of plausible values for a population parameter, calculated from sample data. A 95 percent confidence level means that repeated sampling would produce intervals containing the true parameter about 95 percent of the time. It describes the precision of the estimate, not the probability that one specific interval is correct.

Question 30

What is a hypothesis test and what do the null and alternative hypotheses represent?

Accepted Answer

A hypothesis test is a structured method for deciding whether sample evidence supports a claim about a population. The null hypothesis states that there is no effect or no difference, while the alternative hypothesis states what the team hopes to show, such as a difference or improvement.

Question 31

What is a p-value and what is a common misunderstanding about it?

Accepted Answer

A p-value is the probability of observing data at least as extreme as the sample results, assuming the null hypothesis is true. A small p-value is evidence against the null hypothesis. A common misunderstanding is that the p-value is the probability the null hypothesis is true, which it is not.

Question 32

What is the difference between a Type I error and a Type II error?

Accepted Answer

A Type I error occurs when a true null hypothesis is wrongly rejected, meaning the team concludes an effect exists when it does not. A Type II error occurs when a false null hypothesis is not rejected, meaning a real effect is missed. The significance level sets the Type I error risk.

Question 33

What is a Six Sigma project charter and what does it include?

Accepted Answer

A project charter is a short document that launches a Six Sigma project by stating its business case, problem statement, goal, scope, team members, and timeline. It gives the team authority and a shared understanding of what success looks like. Sponsors approve it and it guides decisions when scope or priorities change.

Question 34

What are the Six Sigma belt levels, and what does a Black Belt typically do?

Accepted Answer

Common belt levels include White, Yellow, Green, and Black Belt, with Master Black Belt above them. A Black Belt typically leads complex improvement projects full time, applies advanced statistical methods, and coaches Green Belts. Belt colors indicate training depth and role, though specific certification requirements vary by organization.

Question 35

What is the purpose of the Analyze phase in DMAIC?

Accepted Answer

The Analyze phase uses data and statistical tools to identify the root causes of defects or excessive variation. Teams form hypotheses about what drives the problem, test them with graphical analysis, hypothesis tests, or designed experiments. The goal is to confirm which few factors matter, rather than relying on opinions or assumptions about causes.

Question 36

What is the purpose of the Improve phase in DMAIC?

Accepted Answer

The Improve phase develops, tests, and implements solutions that address the confirmed root causes. Teams often generate multiple options, evaluate them against cost, risk, and feasibility, and run pilot tests before full rollout. Techniques such as design of experiments and failure mode analysis help the team select and verify changes that reduce defects.

Question 37

What is the purpose of the Control phase in DMAIC?

Accepted Answer

The Control phase sustains the gains achieved by the improvement. Teams update documentation and standard operating procedures, train operators, and set up monitoring, often with control charts, so that deviations are detected early. A response plan defines who acts when signals appear, preventing the process from slowly drifting back to its old performance.

Question 38

What is measurement system analysis and why is it performed first?

Accepted Answer

Measurement system analysis evaluates whether a measuring process is accurate and precise enough for its intended use. It examines bias, linearity, stability, repeatability, and reproducibility. It is performed first because data from a faulty gauge or inconsistent measurement method can mislead every later decision, making improvements look like progress or hiding real problems.

Question 39

What is process capability and how is it judged against specification limits?

Accepted Answer

Process capability describes how well a stable process can produce output within its specification limits. It is summarized with indices such as Cp and Cpk, which compare the spread of process variation to the width of the specification range. Higher values indicate that the process fits the specifications comfortably.

Question 40

What is a failure mode and effects analysis and what is its purpose?

Accepted Answer

Failure mode and effects analysis is a proactive method for identifying how a product or process could fail, what effects those failures would have, and how likely and detectable they are. Teams score each risk by severity, occurrence, and detection, then prioritize actions to reduce the most serious ones before problems occur.

Quality Management and Six Sigma Flashcards

1Quality Management Foundations

2Quality Tools and Process Thinking

3Six Sigma Fundamentals

4Statistical Concepts for Six Sigma

5Applying Six Sigma Projects

Learning Resources