This highly accessible text gives students a solid foundation in traditional inferential statistics with the concepts of quality, variability, and process unifying themes. It covers three important features of data-center, distribution shape, and variation-for processes as well as for populations. The book also explores whether a process is statistically stable and show how analysis of an unstable process can easily lead to incorrect, misleading, and costly decisions. It develops control charts and uses them as a statistical tool to track processes. It also covers the techniques for measuring and understanding variation, and details its effects on costs and quality.