ABSTRACT
All data collected in engineering, manufacturing, or scientific investigations are subject to variability. Variability in data makes decisions more difficult. However, precise results are rare in process research, and variability is a fact of life. We must learn to make informed decisions in the face of uncertain or variable information. Already in this book we have discussed much about variability, and decision making in the presence of variability. In Chapter 2 we discussed some ways of summarizing data (histograms, sample variances, etc.) to reveal the amount of variability present. We also discussed some of the theory for explaining the cause for variability.
