Fundamental Statistical Concepts

The reader, particularly if they happen to be a statistician, may wonder if it is useful to introduce in this book a short course on probabilities (i.e., study of random variables prior to experimentation) and especially on statistics (i.e., study of random variables using data provided by experimentation). The answer is a definite yes and the reason is simple: the author, who has given more than 500 short courses on sampling, and who has been in contact with many clients having sampling problems, found that most people involved with sampling in quality assurance and quality control circles have no basic knowledge of descriptive statistics or long ago forgot this knowledge. Nevertheless, because much software is available and many articles cover the subject of sampling in a very short and superficial way, for better or worse, these people are using statistical concepts. Therefore, it is necessary to include this chapter on fundamental statistical concepts, so these wonderful tools are not misused.