Cheat sheet

ASQ CQE Cheat Sheet

Quick Facts

Exam
ASQ CQE
Questions
175 CBT, 160 scored
Unscored
15 pretest items
Exam time
5 h 18 min
Appointment
5.5 hours total
Pass
Scaled score 550
Pass rate
69% in 2024
Format
Open book, bound references
Delivery
Prometric testing windows
Fee
$550; members $450
Experience
8 years, 3 deciding
Recertify
18 RUs every 3 years

Quality Philosophies

Deming
System owns most variation14 points
Juran
Fitness for useTrilogy
Crosby
Conformance to requirementsZero defects
Feigenbaum
Total quality control
Ishikawa
Fishbone, quality circles
Taguchi
Loss function, robust design
Shewhart
Control charts, plan-do-study-act
Six Sigma
DMAIC projects, 3.4 DPMO

Teams and Facilitation

RACI
Exactly one accountable owner
Responsible
Performs the actual work
Consulted
Two-way input before deciding
Informed
One-way update afterward
Brainstorming
Open generation, no ranking
Nominal group technique
Silent write, round-robin, rank
Force-field analysis
Driving versus restraining forces
Facilitator
Owns process, not content

Benchmarking and Metrics

Internal benchmarking
Units inside same organization
Competitive benchmarking
Direct rival comparison
Functional benchmarking
Same function, other industry
Generic benchmarking
Similar process anywhere
Cost-benefit analysis
Gains weighed against cost
Gantt chart
Schedule bars over time

Customer and Supplier

Stakeholder analysis
Identify who is affected
Satisfaction survey
Direct voice of customer
Supplier qualification
Approve before first order
Supplier certification
Reduces receiving inspection
Supplier rating
Score quality, delivery, cost
Business continuity
Plan for major disruption

Cost of Quality Categories

PAF: Prevention, Appraisal, Failure

Prevention: planning, trainingAppraisal: inspection, testInternal failure: before shipmentExternal failure: after shipmentConformance: prevention plus appraisal

Quality System Documents

Quality manual
Policy and scopeLevel 1
Procedures
Who does what, whenLevel 2
Work instructions
How a task runsLevel 3
Records
Objective evidence of executionLevel 4
Document control
Right version at use
Configuration management
Control baseline and changes
Quality policy
Top management intent statement

Documentation Levels

Manual, Procedures, Instructions, Records

Level 1: quality manualLevel 2: proceduresLevel 3: work instructionsLevel 4: records

Audit Types and Roles

First party
Organization audits itself
Second party
Customer audits its supplier
Third party
Independent registrar or regulatorCertifies
Product audit
Item against its specification
Process audit
One process as documented
System audit
Whole QMS against standard
Client
Requests and commissions audit
Auditee
Organization being audited
Follow-up
Verify corrective action worked

Cost of Quality

Prevention
Stop defects from happening
Appraisal
Inspection, test, audit cost
Internal failure
Found before shipment
External failure
Found by the customerCostliest
Cost of conformance
Prevention plus appraisal
Cost of nonconformance
Internal plus external failure
Hidden quality cost
Unrecorded rework and delay

Standards Map

ISO 9001
QMS requirementsCertifiable
ISO 9000
Vocabulary and fundamentals
ISO 9004
Sustained success guidance
ISO 19011
Auditing management systems
ISO 31000
Risk management guidance
Baldrige
Seven-category excellence frameworkAward, not certificate
ANSI/ASQ Z1.4
Attributes sampling standard
ANSI/ASQ Z1.9
Variables sampling standard

Weibull Beta Shapes

Beta under one infant, over one wear-out

Beta below 1: decreasing rateBeta = 1: exponential, randomBeta above 1: wear-outBathtub combines all three

Verification vs Validation

Verification

  • Built the product right
  • Meets written specification
  • IQ and OQ

Validation

  • Built the right product
  • Meets real user needs
  • PQ in production

Specification vs intended use

Drawings and Specifications

Basic dimension
Boxed, exact, no tolerance
Feature control frame
Carries the geometric tolerance
Datum
Reference origin for measurement
Title block
Scale, units, revision level
MMC
Maximum material conditionBonus tolerance
LMC
Least material condition
Bilateral tolerance
Plus and minus both
Unilateral tolerance
One direction only
Critical to quality
Customer-driven key characteristic

Verification and Validation

Verification
Output meets the specification
Validation
Product meets user needs
IQ
Installed and configured correctly
OQ
Works across operating range
PQ
Consistent output, real production
DFX
Design for manufacturability, serviceability
DFSS
Design for Six Sigma
Requirements traceability
Link need to test
Design review
Staged cross-functional gate

Reliability Indices

MTBF
Repairable, time between failures
MTTF
Non-repairable, time to failure
MTTR
Mean time to repair
Failure rate
Lambda, failures per time
Availability
MTBF/(MTBF+MTTR)Inherent
Exponential model
Constant rate, MTBF=1/lambda
Series system
Multiply component reliabilities
Active parallel
One minus product of unreliabilities
Bathtub curve
Infant, useful life, wear-out

FMEA and Hazard Tools

RPN
Severity x occurrence x detection1 to 1000
Severity
Effect on the customer
Occurrence
How often cause happens
Detection
10 means controls missInverted scale
dFMEA
Design failure modes
pFMEA
Process failure modes
uFMEA
Use and misuse modes
FMECA
FMEA plus criticality analysis
Hazard analysis
Safety hazards and controls

Producer's vs Consumer's Risk

Producer's risk

  • Good lot rejected
  • Alpha, about 0.05
  • Read at AQL

Consumer's risk

  • Bad lot accepted
  • Beta, about 0.10
  • Read at LTPD

AQL protects seller, LTPD buyer

Sampling Plan Picker

  1. Count good or badZ1.4 attributes
  2. Measure one dimensionZ1.9 variables(Assumes normality)
  3. Protect the producerAQL point(Alpha near 0.05)
  4. Protect the consumerLTPD point(Beta near 0.10)
  5. Need sharper discriminationIncrease sample size(Not lot size)
  6. Want a more lenient planRaise acceptance number
  7. Two of five lots rejectedTightened inspection
  8. Consistently good historyReduced inspection
  9. Five tightened lots rejectedStop the sampling(Z1.4 rule)
  10. Costly or destructive testSpecial inspection level(S-1 to S-4)
  11. One isolated lotType A curve(Hypergeometric)

Acceptance Sampling

AQL
Worst still-acceptable quality levelPa 0.95
LTPD
Poor quality, rarely acceptedPa 0.10
RQL
Another name for LTPD
OC curve
Acceptance probability versus quality
Producer's risk
Alpha, good lot rejected
Consumer's risk
Beta, bad lot accepted
AOQ
Average outgoing quality
AOQL
Worst average outgoing qualityCurve maximum
ATI
Average total units inspected
Type A curve
Isolated lot, hypergeometric
Type B curve
Continuous stream, binomial

Repeatability vs Reproducibility

Repeatability

  • Equipment variation
  • One operator, one gage
  • Within-appraiser spread

Reproducibility

  • Appraiser variation
  • Different operators, same part
  • Between-appraiser spread

Gage varies vs people vary

Sampling Standards

Z1.4
Attributes, indexed by AQL
Z1.9
Variables, assumes normal distribution
General level II
Default inspection level
Special levels
S-1 through S-4Small samples
Code letter
Lot size to sample
Normal inspection
Standard starting state
Tightened inspection
Two of five rejected
Reduced inspection
Consistent good history
Discontinue rule
Five tightened lots rejected

Rework vs Repair

Rework

  • Restores full conformance
  • Meets original specification
  • No concession needed

Repair

  • Usable but nonconforming
  • Needs documented concession
  • Customer approval typical

Conforming vs merely acceptable

Metrology and Calibration

Traceability
Unbroken chain to NIST
Calibration interval
Set by risk and drift
Measurement error
Bias plus random variation
Rule of ten
Gage ten times finer
Gage blocks
Length reference standards
CMM
Coordinate measuring machine
Optical comparator
Projects magnified part profile
Destructive test
Part unusable afterward

Z1.4 vs Z1.9

Z1.4

  • Attributes sampling
  • Count nonconforming units
  • Any number of characteristics

Z1.9

  • Variables sampling
  • Measure one characteristic
  • Smaller sample, assumes normal

Count versus measure

Gage R&R Terms

Repeatability
Equipment variation, one operator
Reproducibility
Appraiser variation between operators
GRR under 10%
Generally acceptable systemAccept
GRR 10 to 30%
Acceptable depending on application
GRR over 30%
Unacceptable, fix systemReject
Bias
Average differs from reference
Linearity
Bias changes across range
Stability
Bias drifts over time
ndc
Number of distinct categoriesFive or more

Material Control

MRB
Board deciding nonconforming disposition
Use as is
Accept with no change
Rework
Restores full conformance
Repair
Usable but still nonconformingNeeds concession
Scrap
Discard, cannot be used
Return to supplier
Send back for credit
Segregation
Physically separate nonconforming stock
Lot traceability
History, location, application record

Eight Lean Wastes

DOWNTIME

DefectsOverproductionWaitingNon-utilized talentTransportationInventoryMotionExtra processing

Correction vs Corrective Action

Correction

  • Fixes the affected item
  • Rework, repair, scrap
  • No cause analysis

Corrective action

  • Eliminates the cause
  • Prevents recurrence
  • Effectiveness verified

Fix the part vs cause

Improvement Method Picker

  1. Small local incremental changePDCA(Fast loop)
  2. Unknown cause, high stakesDMAIC(Six Sigma project)
  3. New product or processDMADV(DFSS)
  4. Short intense team eventKaizen event
  5. Organize causes before dataFishbone diagram
  6. Find the vital fewPareto chart(80/20)
  7. Organize many verbal ideasAffinity diagram
  8. Sequence tasks and deadlinesActivity network diagram
  9. Anticipate what could failPDPC

Seven QC Tools

Flowchart
Map the process steps
Pareto chart
Separate the vital few80/20
Cause and effect
Fishbone organizes hypotheses
Control chart
Common versus special cause
Check sheet
Structured tally collection
Scatter diagram
Two-variable relationship plot
Histogram
Distribution shape and spread

Basic Tools Recall

Flow, Pareto, Fish, Chart, Check, Scatter, Histogram

Handles numerical dataFishbone works before dataPareto finds vital fewControl chart tests stability

Seven Management Tools

Affinity diagram
Group ideas into themes
Tree diagram
Break goal into tasks
PDPC
Anticipate what could fail
Matrix diagram
Relate two or more lists
Interrelationship digraph
Find drivers and outcomes
Prioritization matrix
Weighted option ranking
Activity network diagram
Sequence and critical path

Lean Tools

5S
Sort, set, shine, standardize, sustain
Value stream mapping
Material and information flow
Kanban
Pull signal for replenishment
Visual control
Status obvious at glance
Standardized work
Best known method documented
Takt time
Available time / demandCustomer pace
Cycle time
Actual time per unit
SMED
Single minute exchange die
OEE
Availability x performance x qualityThree rates multiply

Corrective and Preventive Action

Correction
Fixes this item only
Corrective action
Removes cause of nonconformity
Preventive action
Removes cause of potential
5 Whys
Ask why until cause
Root cause analysis
Find the true origin
Recurrence control
Stop it happening again
Verification of effectiveness
Prove the fix held
Prevention poka-yoke
Error physically impossiblePreferred
Detection poka-yoke
Signals the error immediately

Chart Selection

Variables: Xbar-R, ImR. Attributes: p, np, c, u

Xbar-R: subgroups 2-9ImR: single readingsp, np: nonconforming unitsc, u: nonconformities

Cp vs Cpk

Cp

  • Potential capability
  • Ignores centering
  • (USL-LSL)/6 sigma

Cpk

  • Actual capability
  • Penalizes off-center mean
  • Minimum of Cpu, Cpl

Cpk never exceeds Cp

Control Chart Picker

  1. Variables, subgroup 2-9Xbar-R(Range estimates spread)
  2. Variables, subgroup 10+Xbar-s(Std dev better)
  3. Variables, one readingImR chart(Needs normality)
  4. Slow process, smoothing wantedMAmR chart
  5. Nonconforming units, varying np chart(Proportion)
  6. Nonconforming units, constant nnp chart(Count)
  7. Nonconformities, constant unitc chart(Poisson)
  8. Nonconformities, varying unitu chart(Per unit)
  9. Short production runsShort-run SPC(Code to target)

Distributions

Normal
Symmetric continuous bell shape
Uniform
Equal probability across range
Exponential
Constant failure rate life
Lognormal
Right-skewed, repair times
Weibull
Shape parameter fits anything
Student's t
Small samples, unknown sigma
F
Ratio of two variances
Chi-square
Variance and goodness-of-fit
Binomial
Fixed trials, constant probability
Poisson
Counts per constant interval
Hypergeometric
Finite lot, no replacement
Multinomial
More than two outcomes

Cpk vs Ppk

Cpk

  • Within-subgroup sigma
  • Rbar/d2 estimate
  • Short-term capability

Ppk

  • Overall sample sigma
  • Includes between-subgroup drift
  • Long-term performance

Wide gap signals instability

Hypothesis Test Picker

  1. One mean, sigma knownZ test
  2. One mean, sigma unknownt test(n-1 degrees freedom)
  3. Two independent meansTwo-sample t test
  4. Before and after, same unitsPaired t test
  5. Three or more meansANOVA F test(Then post-hoc)
  6. Compare two variancesF test
  7. One variance versus targetChi-square test
  8. Does data fit distributionGoodness-of-fit test
  9. Two categorical variablesContingency table(Chi-square)
  10. Compare two proportionsTwo-proportion Z test

Inference Terms

Population
Whole group of interest
Sample
Subset actually measured
Parameter
True population value
Statistic
Value computed from sample
Standard error
Sigma over root n
Central limit theorem
Sample means approach normal
Confidence interval
Range for a parameter
Tolerance interval
Range for individual values
Alpha
Type I error probability
Beta
Type II error probability
Power
One minus betaRaise with n
p-value
Evidence against the null

Type I vs Type II

Type I error

  • Reject a true null
  • Probability alpha
  • Producer's risk

Type II error

  • Keep a false null
  • Probability beta
  • Consumer's risk

False alarm vs missed signal

Capability Index Picker

  1. Process not in controlFix stability first(Capability invalid)
  2. Short-term, within subgroupCp and Cpk
  3. Long-term, all dataPp and Ppk
  4. Centering does not matterCp(Potential only)
  5. Centering mattersCpk(Min Cpu, Cpl)
  6. Target value mattersCpm(Taguchi index)
  7. One-sided specification onlyCpu or Cpl

Relationships Between Variables

r
Direction and strength, -1 to 1
r-squared
Proportion of variation explained
Linear regression
Fit line, predict response
ANOVA F
MSB divided by MSW
Contingency table
Two categorical variables, independence
Moving average
Smooths time series trend

Control vs Specification Limits

Control limits

  • Calculated from process
  • Three sigma of statistic
  • Voice of process

Specification limits

  • Set by customer
  • Apply to individual parts
  • Voice of customer

Never plot specs on Xbar

Control Charts

Xbar-R
Variables, subgroup two to nine
Xbar-s
Variables, subgroup ten plus
ImR
Individuals and moving range
MAmR
Moving average, moving range
p chart
Proportion nonconforming, varying n
np chart
Number nonconforming, constant n
c chart
Nonconformities, constant inspection unit
u chart
Nonconformities per unit, varying
Rational subgrouping
Common cause within subgroup
Short-run SPC
Coded deviation from target

Common vs Special Cause

Common cause

  • Inherent random variation
  • Process is stable
  • Management changes system

Special cause

  • Assignable, outside system
  • Signals on chart
  • Local investigation first

System noise vs assignable event

Control Chart Constants

A2
Xbar-R limit factor
A3
Xbar-s limit factor
d2
Converts Rbar to sigma
D3
Lower R limit factor0 below n=7
D4
Upper R limit factor
E2
Individuals chart limit factor
n=2
d2=1.128, D4=3.267, E2=2.660
n=5
d2=2.326, A2=0.577, D4=2.114

Out-of-Control Rules

1 beyond 3 sigma
Classic out-of-control signalWestern Electric
2 of 3 beyond 2 sigma
Same side of centerWestern Electric
4 of 5 beyond 1 sigma
Same side of centerWestern Electric
8 in a row
One side of centerlineWestern Electric
Points hug centerline
Suspect stratification or mixing
Cycles or trends
Nonrandom systematic pattern

Capability Indices

Cp
(USL-LSL)/6 sigmaPotential
Cpk
Minimum of Cpu, CplActual
Cpu
(USL-xbar)/3 sigma
Cpl
(xbar-LSL)/3 sigma
Cpm
Penalizes deviation from targetTaguchi
Cr
Inverse of CpLower is better
Pp
Overall sigma, ignores centering
Ppk
Overall sigma, includes centering
Sigma within
Rbar/d2 from chart
Sigma overall
Standard deviation, all data
DPMO
Defects per million opportunities
PPM
Parts per million defective
Natural process limits
Mean plus minus 3 sigma

DOE Terms

Factor
Input variable being changed
Level
Setting of a factor
Response
Measured output variable
Treatment
One factor level combination
Replication
Repeat runs estimate error
Randomization
Protects against lurking variables
Blocking
Removes known nuisance variation
Interaction
Effect depends on another
Confounding
Effects cannot be separated
Full factorial
2^k runs, all effects
Fractional factorial
2^(k-p) runs, aliased effects
Resolution III
Main effects alias two-factor
Resolution IV
Main effects clear, two-factor aliased
Resolution V
Two-factor interactions stay clear

Risk Treatment Choices

Avoid, Mitigate, Transfer, Accept

Avoid: drop the activityMitigate: add controlsTransfer: insure or contractAccept: retain residual risk

Risk Terminology

Risk
Effect of uncertainty
Severity
Consequence if it happens
Occurrence
Likelihood it happens
Detection
Chance controls catch it
Inherent risk
Before any control applied
Residual risk
After treatment and controlsSign off here
Risk appetite
Exposure willingly accepted
Risk-based thinking
Prioritize effort by risk

Risk Types

Enterprise risk
Strategic, regulatory, business-wide
Operational risk
Supplier, project, quality system
Product risk
Design, process, use, safety
Supply chain risk
Disruption across supplier tiers
Regulatory risk
Compliance and approval exposure
Safety risk
Harm to people

Risk Treatment and Register

Avoid
Do not do it
Mitigate
Reduce severity or likelihood
Transfer
Insurance or contract termsCost moves only
Accept
Consciously retain residual risk
Risk register
Living log of risks
Risk owner
Named accountable person
Risk matrix
Severity against likelihood gridIgnores detection
Acceptability criteria
Threshold for treating risk
Mitigation plan
Actions, owners, due dates

Risk Monitoring

Complaint tracking
Customer signals after release
Trending
Field and warranty data
Post-market surveillance
Ongoing real-use monitoring
Control testing
Audit whether controls work
Reopen the FMEA
Rising trend triggers revision
Gap analysis
Missing or weak controls

Common Traps

Verification vs validation

Verification checks the specification Validation checks intended use

Cp vs Cpk

Cp ignores centering Cpk penalizes off-center mean

Control vs specification limits

Control limits from process Spec limits from customer

Alpha vs beta

Alpha rejects good lots Beta accepts bad lots

Rework vs repair

Rework restores full conformance Repair needs documented concession

Repeatability vs reproducibility

Repeatability is the equipment Reproducibility is the appraisers

Correction vs corrective action

Correction fixes the item Corrective action removes cause

Detection rating direction

Detection 10 means missed Detection 1 means caught

Sample size vs lot size

Sample size drives discrimination Lot size barely matters

Inherent vs residual risk

Inherent is before controls Residual is after treatment

MTBF vs MTTF

MTBF for repairable items MTTF for discarded items

Calibration vs traceability

Sticker shows calibration date Traceability needs unbroken chain

Last Minute

  1. 1.160 scored questions, 15 unscored
  2. 2.Quantitative Methods is largest, 34 questions
  3. 3.Cp = potential; Cpk = centered
  4. 4.Cpk uses within-subgroup sigma; Ppk overall
  5. 5.Alpha = producer risk; beta = consumer
  6. 6.AQL sits near 0.95 acceptance
  7. 7.LTPD sits near 0.10 acceptance
  8. 8.GRR under 10% is acceptable
  9. 9.GRR over 30% is unacceptable
  10. 10.MTBF = 1/lambda when rate constant
  11. 11.Series multiplies R; parallel multiplies unreliability
  12. 12.Availability = MTBF/(MTBF+MTTR)
  13. 13.RPN = severity x occurrence x detection
  14. 14.Detection 10 means controls miss it
  15. 15.Z1.4 counts; Z1.9 measures
  16. 16.Never plot specs on Xbar chart
  17. 17.Correction fixes item; corrective removes cause
  18. 18.Takt = available time / demand
  19. 19.OEE = availability x performance x quality
  20. 20.Residual risk drives acceptance decisions
  21. 21.Exam is open book, bound references
  22. 22.No alphabetic-keyboard calculators; clear memory
  23. 23.Passing scaled score is 550
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