PECB Six Sigma Green Belt flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Six Sigma definition

A disciplined, data-driven methodology that reduces process variation and defects to 3.4 DPMO, using DMAIC to improve existing processes and DMADV for new designs.

DPMO formula

Defects per million opportunities equals defects divided by (units multiplied by opportunities per unit), then multiplied by one million. Used to compare processes of differing complexity.

DMAIC phases

Define, Measure, Analyze, Improve, Control. A structured improvement cycle for existing processes, each phase gated by deliverables such as the charter, baseline data, and verified results.

Eight wastes (Lean)

Defects, overproduction, waiting, non-utilized talent, transportation, inventory, motion, and extra processing. Each consumes resources without adding customer value and is a target for elimination.

Rolled throughput yield

The product of first-pass yields at each process step. It exposes hidden factory losses that final inspection yield masks, because rework and scrap reduce true throughput.

Value-added criteria

A step is value-added only if it changes form, fit, or function, the customer is willing to pay for it, and it is done correctly the first time.

Belt roles and responsibilities

Champion sponsors projects and removes barriers; Master Black Belt provides technical coaching; Green Belt leads projects part-time; Yellow Belt supports with basic tools and data collection.

Project selection criteria

Candidates should link to strategic goals, have a measurable output with a baseline, a clear owner, feasible resources, and be completable in roughly three to six months.

Project charter elements

Problem statement, goal statement, scope and boundaries, business case, team members, milestones, and constraints. The charter authorizes the project and aligns stakeholders on expectations.

Problem statement rules

State the gap with data, including magnitude, time, and location. Do not name a cause or a solution, which would bias the analysis before data are collected.

SMART goal statement

Specific, measurable, achievable, relevant, and time-bound. A Six Sigma goal includes the metric, baseline, target, and completion date, stated without implying a solution.

SIPOC diagram purpose

Maps Suppliers, Inputs, Process, Outputs, and Customers at a high level. It clarifies project boundaries and shows where the process starts and stops.

CTQ tree

A tool that translates voice of the customer needs into measurable critical-to-quality characteristics, then into specifications that can be measured and controlled.

Stakeholder influence-interest grid

Plots stakeholders by influence and interest. High-influence, high-interest parties receive active engagement; low-interest parties receive periodic updates only.

Repeatability vs reproducibility

Repeatability is variation when the same appraiser measures the same item repeatedly with one instrument. Reproducibility is variation between different appraisers using the same instrument.

Gage R&R acceptance

Percent GRR below 10 percent is acceptable, 10 to 30 percent is conditionally acceptable depending on cost and application, and above 30 percent is unacceptable.

Attribute agreement kappa

A chance-corrected agreement statistic for attribute measurement systems. Values above 0.75 indicate good agreement; values near zero indicate agreement no better than chance.

Cp capability index

Cp equals (USL minus LSL) divided by six sigma. It measures process spread relative to tolerance width and ignores centering, so it can look good while the process is off target.

Cpk capability index

Cpk equals the minimum of (USL minus mean) divided by three sigma and (mean minus LSL) divided by three sigma. It accounts for both spread and centering.

Rational subgrouping

Subgroups are formed so that units within a subgroup share conditions and capture only common-cause variation, while subgroups span time to reveal special causes.

Operational definition

A precise, agreed description of how a characteristic is measured, including instrument, procedure, and decision criteria, so different people collect comparable data.

Continuous vs discrete data

Continuous data are measured on a scale and support powerful tests with small samples. Discrete or attribute data are counted and typically require larger samples to detect differences.

MSA before capability

Measurement system analysis is performed before capability studies, because measurement variation inflates observed variation and can make an adequate process appear incapable.

Five Whys technique

Repeatedly asking why a problem occurs to move from symptoms to root cause. Each answer is verified with data rather than assumed, typically stopping when the cause is actionable.

Fishbone diagram

An Ishikawa cause-and-effect diagram organizing potential causes into categories such as man, machine, material, method, measurement, and environment. It structures brainstorming before data verification.

Pareto principle

Roughly 80 percent of problems arise from 20 percent of causes. A Pareto chart ranks categories by frequency or cost to identify the vital few worth attacking first.

Type I and Type II error

Type I error rejects a true null hypothesis (false alarm, risk alpha). Type II error fails to reject a false null hypothesis (missed effect, risk beta).

Statistical power

Power equals one minus beta, the probability of detecting a real effect. It increases with larger sample size, larger effect size, and lower variability, commonly targeted at 0.80.

ANOVA purpose

Analysis of variance compares the means of three or more groups by testing whether between-group variation exceeds within-group variation. A significant result indicates at least one mean differs.

FMEA RPN

Risk Priority Number equals Severity multiplied by Occurrence multiplied by Detection. Higher values prioritize action, and high severity alone can require action regardless of RPN.

Poka-yoke

Mistake-proofing that prevents errors from being made or from passing to the next step, through design features such as fixtures, sensors, or checklists. Preferred over inspection.

Control plan contents

Documents the monitored characteristic, specification, measurement method, sample size and frequency, control method, and reaction plan when out-of-control conditions occur.