Third Edition

Amitava Mitra

PREFACE xix

PART1 PHILOSOPHYAND FUNDAMENTALS 1

1 Introductionto Quality Control and the Total Quality System

1-1 Introductionand Chapter Objectives, 31-2 Evolutionof Quality Control, 41-3 Quality, 7

Quality Characteristics, 8Variablesand Attributes, 8Defects, 9Standard or Specification, 9Quality of Design, 9Quality of Conformance, 10Quality of Performance, 11

1-4 QualityControl, 11Off-Line Quality Control, 12Statistical Process Control, 12Acceptance Sampling Plans, 12

1-5 Quality Assurance, 131-6 Quality Circ1esand Quality Improvement Teams, 141-7 Customer Needs and Market Share, 15

Kano Model, 151-8 Benefitsof Quality Control and the Total Quality System, 16

Total Quality System, 171-9 Quality and Reliability, 171-10 Quality Improvement, 181-11 Product and Service Costing, 19

Activity-Based Costing, 191-12 Quality Costs, 22

Prevention Costs, 23Appraisal Costs, 23

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Internal Failure Costs, 23External Failure Costs, 24Hidden Failure Costs, 24Quality Costs Data Requirements, 24Proeess Cost Approaeh, 25

1-13 Measuring Quality Costs, 26

Impaet of Quality Improvement on Quality Costs, 281-14 Management of Quality, 301-15 Quality and Produetivity, 33

Effeet on Cost, 33Effeet on Market, 33

1-16 Total Quality Environmental Management, 361-17 Profile of a Company: The Bama Companies, Ine., 37

Company History and Vision, 37Eyes on Quality, 38The Future Looks Bright, 38Innovation and Quality Improvement, 38People Make the Company, 39

Summary, 39Key Terms, 40Exercises, 40Referenees, 44

2 Some Philosophies aod Their Impact 00 Quality

2-1 Introduetion and Chapter Objeetives, 472-2 Serviee Industries and Their Charaeteristies, 48

Differenees in the Manufaeturing and Serviee Seetors, 48Serviee Quality Charaeteristies, 50Measuring Service Quality, 52Teehniques for Evaluating Service Quality, 52

2-3 Model for Service Quality, 532-4 W. Edwards Deming's Philosophy, 56

Extended Proeess, 57Deming's 14 Points for Management, 58Deming's Deadly Diseases, 72

2-5 Philip B. Crosby's Philosophy, 75

Four Absolutes of Quality Management, 76l4-Step Plan for Quality Improvement, 76

2-6 Joseph M. Juran's Philosophy, 78Quality Trilogy Proeess, 79Quality Planning, 79Quality Control, 80Quality Improvement, 81

2-7 The Three Philosophies Compared, 82Definition of Quality, 82Management Commitment, 82

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x LU1~ lDl~ 1"

PART n STATISTICAL FOUNDATIONS AND METHODS

OF QUALITY IMPROVEMENT 147

4 Fundamentals of Statistical Concepts and Techniqnes inQuality Control and lmprovement

4-1 Introduction and Chapter Objectives, 1494-2 Population and Sample, 1504-3 Parameter and Statistic, 1504-4 Probability, 150

Relative Frequency Definition of Probability, 150Simple and Compound Events, 151Complementary Events, 152Additive Law, 153Multiplicative Law, 153Independence and Mutually Exc1usiveEvents, 154

4-5 Descriptive Statistics: Describing Product or Process Characteristics, 156Data Collection, 156Measurement Scales, 158Measures of Central Tendency, 159Measures of Dispersion, 161Measures of Skewness and Kurtosis, 166Measures of Association, 169

4-6 Probability Distributions, 173Cumulative Distribution Function, 175Expected Value, 175Discrete Distributions, 176Continuous Distributions, 180

4-7 Inferential Statistics: Drawing Conc1usionsonProduct and Process Quality, 188

Sampling Distributions, 189Estimation of Product and Process Parameters, 190Hypothesis Testing, 199

Summary, 210Appendix: Approximations to Some ProbabilityDistributions, 211

Binomial Approximation of the Hypergeometric, 211Poisson Approximation to the Binomial, 211Normal Approximation to the Binomial, 212Normal Approximation to the Poisson, 212

Key Terms, 213Exercises, 214References, 227

149

5 Data Analyses and Sampling

5-1 Introduction and Chapter Objectives, 2295-2 Empirical Distribution Plots, 229

229

Histograms, 229Stem-and-Leaf Plots, 231Box Plots, 232Variations of the Basic Box Plot, 234

5-3 Randomness of a Sequence, 234Run Chart, 235

5-4 Validating Distributional Assumptions, 236Probability Plotting, 237

5-5 Transformations to Achieve Normality, 239Some Common Transformations, 240Power Transformations, 240Johnson Transformation, 240

5-6 Analysis of Count Data, 244Hypothesis Test on Cell Probabilities, 244Contingency Tables, 245Measures of Association, 246

5-7 Concepts in Sampling, 247Sampling Designs and Schemes, 248Sample Size Determination, 250Bound on the Error of Estimation and AssociatedConfidence Level, 250Estimating the Difference of Two Population Means, 252Estimating the Difference of Two PopulationProportions, 252Controlling the Type 1Error, Type II Error, andAssociated Parameter Shift, 253

Summary, 254Key Terms, 255Exercises, 256References, 260

PART 111 STATISTICAL PROCESS CONTROL

6 Statistical Process Control Using Control Charts

6-1 lntroduction and Chapter Objectives, 2656-2 Causes of Variation, 267

Special Causes, 267Common Causes, 267

6-3 Statistical Basis for Control Charts, 267Basic PrincipIes, 267Selection of Control Limits, 269Errors in Making lnferences from Control Charts, 271Effect of Control Limits on Errors in lnference Making, 275Warning Limits, 276Effect of Sample Size on Control Limits, 276Average Run Length, 277

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265

PART IV ACCEPTANCE SAMPLING 465

10 Acceptance Sampling Plans for Attributes and Variables 467

10-110-210-310-4

lntroduction and Chapter Objectives, 467Advantages and Disadvantages of Sampling, 468Producer and Consumer Risks, 468Operating Characteristic Curve, 469

Effect of the Sample Size and theAcceptance Number, 472

10-5 Types of Sampling Plans, 473

Advantages and Disadvantages, 47410-6 Evaluating Sampling Plans, 475

Average Outgoing Quality, 475Average Total Inspection, 477Average Sample Number, 478

10-7 Bayes' Rule and Decision Making Based on Samples, 48010-8 Lot-by-Lot Attribute Sampling Plans, 483

Single Sampling Plans, 483Double Sampling Plans, 490Multiple Sampling Plans, 496Standard Sampling Plans, 497

10-9 Other Attribute Sampling Plans, 501Chain Sampling Plan, 501Sequential Sampling Plan, 503

10-10 Deming's kp Rule, 504

Critique of the kp Rule, 50610-11 Sampling Plans for Variables, 507

Advantages and Disadvantages of Variable Plans, 50710-12 Variable Sampling Plans for a Process Parameter, 508

Estimating Process Average: Single Specification Limitand Known Process Standard Deviation, 508Estimating Process Average: Double Specification Limitsand Known Process Standard Deviation, 510Estimating Process Average: Single Specification Limitand Unknown Process Standard Deviation, 513

10-13 Variable Sampling Plans for Estimating the Lot ProportionNonconforming, 514

Derivation of a Variable Sampling Plan with a SingleSpecification Limit and Known ProcessStandard Deviation, 515Standardized Plans: ANSI/ISO/ASQ Z1.9and MIL-STD-414, 518

Summary, 519Key Terms, 520Exercises, 520References, 526