Preface xix Preface to the Second Edition xxi
Preface to the First Edition xxiii
PART I FUNDAMENTAL QUALITY IMPROVEMENT AND STATISTICAL CONCEPTS
1 Introduction 3
1.1 Quality and Productivity, 4
1.2 Quality Costs (or Does It?), 5
1.3 The Need for Statistical Methods, 5
1.4 Early Use of Statistical Methods for Improving Quality, 6
1.5 Influential Quality Experts, 7
1.6 Summary, 9
2 Basic Tools for Improving Quality 13
2.1 Histogram, 13
2.2 Pareto Charts, 17
2.3 Scatter Plots, 21
2.4 Control Chart, 24
2.5 Check Sheet, 26
2.6 Cause-and-Effect Diagram, 26
2.7 Defect Concentration Diagram, 28
2.8 The Seven Newer Tools, 28
2.9 Software, 30
2.10 Summary, 31
3 Basic Concepts in Statistics and Probability 33
3.1 Probability, 33
3.2 Sample Versus Population, 35
3.3 Location, 36
3.4 Variation, 38
3.5 Discrete Distributions, 41
3.6 Continuous Distributions, 55
3.7 Choice of Statistical Distribution, 69
3.8 Statistical Inference, 69
3.9 Enumerative Studies Versus Analytic Studies, 81
PARTII CONTROL CHARTS AND PROCESS CAPABILITY
4 Control Charts for Measurements With Subgrouping (for One Variable) 89
4.1 Basic Control Chart Principles, 89
4.2 Real-Time Control Charting Versus Analysis of Past Data, 92
4.3 Control Charts: When to Use, Where to Use, How Many to Use, 94
4.4 Benefits from the Use of Control Charts, 94
4.5 Rational Subgroups, 95
4.6 Basic Statistical Aspects of Control Charts, 95
4.7 Illustrative Example, 96
4.8 Illustrative Example with Real Data, 114
4.9 Determining the Point of a Parameter Change, 116
4.10 Acceptance Sampling and Acceptance Control Chart, 117
4.11 Modified Limits, 124
4.12 Difference Control Charts, 124
4.13 Other Charts, 126
4.14 Average Run Length (ARL), 127
4.15 Determining the Subgroup Size, 129
4.16 Out-of-Control Action Plans, 131
4.17 Assumptions for the Charts in This Chapter, 132
4.18 Measurement Error, 140
4.19 Software, 142
4.20 Summary, 143
5 Control Charts for Measurements Without Subgrouping (for One Variable) 157
5.2 Transform the Data or Fit a Distribution?, 170
5.3 Moving Average Chart, 171
5.4 Controlling Variability with Individual Observations, 173
5.5 Summary, 175
6 Control Charts for Attributes 181
6.1 Charts for Nonconforming Units, 182
6.2 Charts for Nonconformities, 202
6.3 Summary, 218
7 Process Capability 225
7.1 Data Acquisition for Capability Indices, 225
7.2 Process Capability Indices, 227
7.3 Estimating the Parameters in Process Capability Indices, 232
7.4 Distributional Assumption for Capability Indices, 235
7.5 Confidence Intervals for Process Capability Indices, 236
7.6 Asymmetric Bilateral Tolerances, 243
7.7 Capability Indices That Are a Function of Percent Nonconforming, 245
7.8 Modified k Index, 250
7.9 Other Approaches, 251
7.10 Process Capability Plots, 251
7.11 Process Capability Indices Versus Process Performance Indices, 252
7.12 Process Capability Indices with Autocorrelated Data, 253
7.13 Software for Process Capability Indices, 253
7.14 Summary, 253
8 Alternatives to Shewhart Charts 261
8.1 Introduction, 261
8.2 Cumulative Sum Procedures: Principles and Historical Development, 263
8.3 CUSUM Procedures for Controlling Process Variability, 283
8.4 Applications of CUSUM Procedures, 286
8.5 Generalized Likelihood Ratio Charts: Competitive Alternative to CUSUM Charts, 286
8.6 CUSUM Procedures for Nonconforming Units, 286
8.7 CUSUM Procedures for Nonconformity Data, 290
8.8 Exponentially Weighted Moving Average Charts, 294
8.9 Software, 301
8.10 Summary, 301
9 Multivariate Control Charts for Measurement and Attribute Data 309
9.1 Hotelling's T2 Distribution, 312
9.2 A T2 Control Chart, 313
9.3 Multivariate Chart Versus Individual X-Charts, 326
9.4 Charts for Detecting Variability and Correlation Shifts, 327
9.5 Charts Constructed Using Individual Observations, 330
9.6 When to Use Each Chart, 335
9.7 Actual Alpha Levels for Multiple Points, 336
9.8 Requisite Assumptions, 336
9.9 Effects of Parameter Estimation on ARLs, 337
9.10 Dimension-Reduction and Variable Selection Techniques, 337
9.11 Multivariate CUSUM Charts, 338
9.12 Multivariate EWMA Charts, 339
9.13 Effect of Measurement Error, 343
9.14 Applications of Multivariate Charts, 344
9.15 Multivariate Process Capability Indices, 344
9.16 Summary, 344
10 Miscellaneous Control Chart Topics 353
10.1 Pre-control, 353
10.2 Short-Run SPC, 356
10.3 Charts for Autocorrelated Data, 359
10.4 Charts for Batch Processes, 364
10.5 Charts for Multiple-Stream Processes, 364
10.6 Nonparametric Control Charts, 365
10.7 Bayesian Control Chart Methods, 366
10.8 Control Charts for Variance Components, 367
10.9 Control Charts for Highly Censored Data, 367
10.10 Neural Networks, 367
10.11 Economic Design of Control Charts, 368
10.12 Charts with Variable Sample Size and/or Variable Sampling Interval, 370
10.13 Users of Control Charts, 371
10.14 Software for Control Charting, 374
PART III BEYOND CONTROL CHARTS: GRAPHICAL AND STATISTICAL METHODS
11 Graphical Methods 387
11.1 Histogram, 388
11.2 Stem-and-Leaf Display, 389
11.3 Dot Diagrams, 390
11.4 Boxplot, 392
11.5 Normal Probability Plot, 396
11.6 Plotting Three Variables, 398
11.7 Displaying More Than Three Variables, 399
11.8 Plots to Aid in Transforming Data, 399
11.9 Summary, 401
12 Linear Regression 407
12.1 Simple Linear Regression, 407
12.2 Worth of the Prediction Equation, 411
12.3 Assumptions, 413
12.4 Checking Assumptions Through Residual Plots, 414
12.5 Confidence Intervals and Hypothesis Test, 415
12.6 Prediction Interval for Y, 416
12.7 Regression Control Chart, 417
12.8 Cause-Selecting Control Charts, 419
12.9 Linear, Nonlinear, and Nonparametric Profiles, 421
12.10 Inverse Regression, 423
12.11 Multiple Linear Regression, 426
12.12 Issues in Multiple Regression, 426
12.13 Software For Regression, 429
12.14 Summary, 429
13 Design of Experiments 435
13.1 A Simple Example of Experimental Design Principles, 435
13.2 Principles of Experimental Design, 437
13.3 Statistical Concepts in Experimental Design, 439
13.4 t-Tests, 441
13.5 Analysis of Variance for One Factor, 445
13.6 Regression Analysis of Data from Designed Experiments, 455
13.7 ANOVA for Two Factors, 460
13.8 The 23 Design, 469
13.9 Assessment of Effects Without a Residual Term, 474
13.10 Residual Plot, 477
13.11 Separate Analyses Using Design Units and Uncoded Units, 479
13.12 Two-Level Designs with More Than Three Factors, 480
13.13 Three-Level Factorial Designs, 482
13.14 Mixed Factorials, 483
13.15 Fractional Factorials, 483
13.16 Other Topics in Experimental Design and Their Applications, 493
13.17 Summary, 500
14 Contributions of Genichi Taguchi and Alternative Approaches 513
14.1 "Taguchi Methods", 513
14.2 Quality Engineering, 514
14.3 Loss Functions, 514
14.4 Distribution Not Centered at the Target, 518
14.5 Loss Functions and Specification Limits, 518
14.6 Asymmetric Loss Functions, 518
14.7 Signal-to-Noise Ratios and Alternatives, 522
14.8 Experimental Designs for Stage One, 524
14.9 Taguchi Methods of Design, 525
14.10 Determining Optimum Conditions, 553
14.11 Summary, 558
15 Evolutionary Operation 565
15.1 EVOP Illustrations, 566
15.2 Three Variables, 576
15.3 Simplex EVOP, 578
15.4 Other EVOP Procedures, 581
15.5 Miscellaneous Uses of EVOP, 581
15.6 Summary, 582
16 Analysis of Means 587
16.1 ANOM for One-Way Classifications, 588
16.2 ANOM for Attribute Data, 591
16.3 ANOM When Standards Are Given, 594
16.4 ANOM for Factorial Designs, 596
16.5 ANOM When at Least One Factor Has More Than Two Levels, 601
16.6 Use of ANOM with Other Designs, 610
16.7 Nonparametric ANOM, 610
16.8 Summary, 611
17 Using Combinations of Quality Improvement Tools 615
17.1 Control Charts and Design of Experiments, 616
17.2 Control Charts and Calibration Experiments, 616
17.3 Six Sigma Programs, 616
17.4 Statistical Process Control and Engineering Process Control, 624
Answers to Selected Exercises 629
Appendix: Statistical Tables 633
Author Index 645
Subject Index 657
