He developed a tool that he called the control chart, which could graphically depict variation. This control chart, could also distinguish the two types of variation from each other, thus allowing for the elimination of special causes and the reduction of common cause variation. There are several types of variables data and attributes data control charts. This section will discuss the different types of control charts, the applications of each control chart, and the interpretation of the data. Types of Control Charts Variables data are quantitative data that can be measured.
Some examples are the diameter of a bearing or the thickness of a newly minted coin.
Attributes data are qualitative data that can be counted. Attributes data are usually represented as nonconforming units and are analyzed by using p, np, c, or u control charts. First, determine what variable you will measure.