Some useful analytical tools and techniques were introduced in the previous chapter. The analysis of data collected in the measure stage depends on the type of data collected, discrete or continuous.

Discrete data analysis primarily involves tools such as Pareto charts, pie charts, and bar diagrams. As discussed earlier, Pareto charts tell us about the significant contributors to the outcome. It is also known as "vital-few-trivial-many" or the 80/20 principle, and is a very effective tool that enables us to focus on the vital factors.

Continuous data analysis involves tools such as frequency distribution diagrams, for example histograms and box plots. Histograms can provide a lot of information about the variation and the central tendency of the process. Some of the common shapes of histograms are given in the following table:

Similar to histograms, box plots also provide information about the variation and the central tendency of the process. A multiple box plot...