Page 4 - Statistics for Environmental Engineers

Preface to 1st Edition

When one is confronted with a new problem that involves the collection and analysis of data, two crucial
questions are: How will using statistics help solve this problem? And, Which techniques should be used?
This book is intended to help environmental engineers answer these questions in order to better under-
stand and design systems for environmental protection.
The book is not about the environmental systems, except incidentally. It is about how to extract
information from data and how informative data are generated in the first place. A selection of practical
statistical methods is applied to the kinds of problems that we encountered in our work. We have not
tried to discuss every statistical method that is useful for studying environmental data. To do so would
mean including virtually all statistical methods, an obvious impossibility. Likewise, it is impossible to
mention every environmental problem that can or should be investigated by statistical methods. Each
reader, therefore, will find gaps in our coverage; when this happens, we hope that other authors have
filled the gap. Indeed, some topics have been omitted precisely because we know they are discussed in
other well-known books.
It is important to encourage engineers to see statistics as a professional tool used in familiar examples
that are similar to those faced in one’s own work. For most of the examples in this book, the environmental
engineer will have a good idea how the test specimens were collected and how the measurements were
made. The data thus have a special relevance and reality that should make it easier to understand special
features of the data and the potential problems associated with the data analysis.
The book is organized into short chapters. The goal was for each chapter to stand alone so one need
not study the book from front to back, or in any other particular order. Total independence of one chapter
from another is not always possible, but the reader is encouraged to “dip in” where the subject of the
case study or the statistical method stimulates interest. For example, an engineer whose current interest
is fitting a kinetic model to some data can get some useful ideas from Chapter 25 without first reading
the preceding 24 chapters. To most readers, Chapter 25 is not conceptually more difficult than Chapter 12.
Chapter 40 can be understood without knowing anything about t-tests, confidence intervals, regression,
or analysis of variance.
There are so many excellent books on statistics that one reasonably might ask, Why write another
book that targets environmental engineers? A statistician may look at this book and correctly say,
“Nothing new here.” We have seen book reviews that were highly critical because “this book is much
like book X with the examples changed from biology to chemistry.” Does “changing the examples” have
some benefit? We feel it does (although we hope the book does something more than just change the
examples).
A number of people helped with this book. Our good friend, the late William G. Hunter, suggested
the format for the book. He and George Box were our teachers and the book reflects their influence on
our approach to engineering and statistics. Lars Pallesen, engineer and statistician, worked on an early
version of the book and is in spirit a co-author. A. (Sam) James provided early encouragement and
advice during some delightful and productive weeks in northern England. J. Stuart Hunter reviewed the
manuscript at an early stage and helped to “clear up some muddy waters.” We thank them all.

P. Mac Berthouex
Madison, Wisconsin

Linfield C. Brown
Medford, Massachusetts

© 2002 By CRC Press LLC