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This book is about the use of modern statistical methods for quality control. It provides comprehensive coverage of the subject from basic principles to state‐of‐the‐art concepts and applications. The objective is to give the reader a sound understanding of the principles and the basis for applying them in a variety of situations. Although statistical techniques are emphasized throughout, the book has a strong engineering and management orientation. Extensive knowledge of statistics is not a prerequisite for using this book. Readers whose background includes a basic course in statistical methods will find much of the material in this book easily accessible.

The book originally grew out of our teaching, research, and consulting in the application of statistical methods for various fields, particularly for industries. It is designed as a textbook for students enrolled in colleges and universities, who are studying engineering, statistics, management, and related fields and are taking a first course in statistical quality control. The basic quality control course is often taught at the junior or senior level. All the standard topics for this course are covered in detail. We have also used the text materials extensively in programs for professional practitioners, including quality and reliability engineers, manufacturing and development engineers, product designers, managers, procurement specialists, marketing personnel, technicians and laboratory analysts, inspectors, and operators.

The book contains eight chapters. Chapter 1 is an introduction of history and background of control charts. This chapter also includes descriptive statistics, the basic notions of probability and probability distributions, and types of control charts. These topics are usually covered in a basic course in statistical methods; however, their presentation in this text is from the quality engineering viewpoint. It describes that quality has become a major business strategy and that organizations that successfully improve quality can increase their productivity, enhance their market penetration, and achieve greater profitability and a strong competitive advantage. Chapter 2 presents the Shewhart‐type attribute control charts for counts. It highlights the importance of attribute data and presents the proper use of statistical methods to implement quality control. Concept of dispersed data is introduced, and control charts used for monitoring over‐ or under‐dispersed data are discussed along with application in industries.

In Chapter 3, control charts for monitoring the variable data processing are presented with basic concepts and implantation on real data sets. These Shewhart control charts certainly are not new, but its use in modern‐day business and industries is of tremendous value. Chapter 4 contains the new idea of control charts for multiple dependent state (MDS) sampling. The MDS sampling showed the efficiency of the attribute control chart over the traditional Shewhart attribute control chart in terms of average run length. The use of MDS sampling in the area of control chart has increased the sensitivity of the control charts to detect a small shift in the manufacturing process. For decision‐making, it uses the current subgroup information and previous subgroup information to make the decision about the state of the process. In Chapter 5, exponentially weighted moving average (EWMA) control charts using repetitive group sampling scheme are introduced. The methods for EWMA‐based control charts for a variety of situations, such as the average and the dispersion monitoring charts, single sampling, double sampling, multiple sampling, sequential sampling, repetitive sampling, ranked set sampling, and the MDS sampling charts have been developed in this chapter.

Chapter 6 presents the different sampling schemes used to construct the control charts. Some of these sampling schemes are very simple to develop and understand, while some schemes are much complex to develop and understand. Each of the sampling schemes has advantages and disadvantages; therefore the quality control personnel can select according to the situation and the available resources. The use of modern statistical software has made a very simple task of developing a control chart for the non‐statisticians' quality control personnel as there is no need to develop and understand the complex sampling schemes. In Chapter 7, memory‐type control charts for monitoring attributes, such as the cumulative sum chart, the EWMA chart, and the moving average charts, are given with application in industries. Chapter 8 contains the material related to multivariate process control schemes. Nowadays, in industry, there are many situations in which the simultaneous monitoring or control of two or more related quality process characteristics is necessary. Monitoring these quality characteristics independently can be very misleading.

Throughout the book, guidelines are given for selecting the proper type of statistical technique to use in a wide variety of situations. Additionally, extensive references to journal articles and other technical literature should assist the reader in applying the methods described.

Muhammad Aslam

Aamir Saghir

Liaquat Ahmad

May 2020