ABSTRACT
This chapter explains the descriptive statistics used most frequently in quality control applications –the measures of central tendency, variability, and shape. Two types of statistics are commonly used in business: descriptive statistics and inferential statistics. Both are critical to the application of basic statistical quality control procedures. Descriptive statistics summarize information and aid in decision making. These descriptive measures are presented strictly from an applications viewpoint. Descriptive statistics show two major features of the sample data they describe. They show the central location of the data, and show the spread or dispersion of the data. For individuals not well versed in statistical analysis, two graphical statistics –the frequency polygon and the frequency histogram –provide a comprehensible summary of data. The arithmetic mean and the standard deviation provide a more definitive description.
