Like the first three volumes, published in 1981, 1984 and 1987 and met with a lively response, the present volume is collecting contributions stressed on methodology or successful industrial applications. The papers are classified under three main headings; sampling inspection, process quality control and experimental design. In the first group there are nine papers on acceptance sampling. The second large group of papers deal with control charts and process control and the third group of papers includes contributions on experimental design.

This book began many years ago as course notes for students at the University of Bath, and later at the University of Kent. Students used draft versions of the chapters, which were consequently revised. Second and third year students, as well as those taking MSc courses have used selections of the chapters. In particular, Chapters I to 7 (only) have been the basis of a very successful second-year course, the more difficult sections being omitted. The aims of this particular course were: - (a) to cover some interesting and useful applications of statistics with an emphasis on applications, but with really adequate theory; (b) to lay the foundations for interesting third-year courses; (c) to tie up with certain areas of pure mathematics and numerical analysis. 2 Students will find Chapter I a useful means of revising the t, X and F procedures, which is material assumed in this text, see Section 1.1. Later sections of Chapter I cover robustness and can be omitted by second-year students or at a first reading. Chapter 2 introduces some simple statistical models, so that the discussion of later chapters is more meaningful

This booklet contains hints to the solutions and answers where necessary, of the exercises contained in 'Intermediate Statistical Methods' by G. Barrie Wetherill. The following principles have been adopted in dealing with the answers. (1) In some cases the answer is the drawing of a graph, and this has been omitted. (2) In many numerical exercises a considerable amount of 'data snooping', plotting of residuals, etc. should follow the main ~sis. The inclusion of this material would make the answer booklet far too long. (3) In some cases there is a readily available reference from which the answer can be ob~ained, in which case reference has been made to this. It is not necessary to work through every exercise , but it should be recognised that the exercises are an integral part of the main text, and a comprehensive grasp of the subj ect cannot be obtained without attempting a substantial proportion of them. It is hoped that this booklet will be of assistance in pointing the way, and providing a check on the more vital calculations. The importance of numerical exercises should be stressed, and it is here that Appendix B is of importance. There is abundant material available there in many different fields of application. Currently we are in the process of mounting a form of Appendix B on a computer, together with accessing programs.

Providing a broad coverage of the principles of sampling inspection and quality control, this latest edition has been revised throughout. Particular emphasis is given to the inclusion of tables and nomograms enabling the setting of numerical exercises.

This book is mainly based on lectures given by Professor D. R. Cox and myself at Birkbeck College over a period of eight to nine years. It began as a joint venture, but pressure of other work made it necessary for Professor Cox to withdraw early on. I have throughout received much valuable advice and encouragement from Professor Cox, but of course, I am solely responsible for the text, and any errors remaining in it. The book is intended as a first course on statistical methods, and there is a liberal supply of exercises. Although the mathematical level of the book is low, I have tried to explain carefully the logical reasoning behind the use of the methods discussed. Some of the exercises which require more difficult mathematics are marked with an asterisk, and these may be omitted. In this way, I hope that the book will satisfy the needs for a course on statistical methods at a range of mathematical levels. It is essential for the reader to work through the numerical exercises, for only in this way can he grasp the full meaning and usefulness of the statistical techniques, and gain practice in the interpretation of the results. Chapters 7 and 8 discuss methods appropriate for use on ranked or discrete data, and Chapters 9-12 do not depend on these chapters. Chapters 7 and 8 may therefore be omitted, if desired.