AVERAGE CHART Meaning and
Definition
-
An average chart, also known as a mean chart or a control chart, is a statistical tool used in quality control to analyze and monitor processes. It provides a graphical representation of the average value of a variable over time.
In a typical average chart, data points are plotted on a graph, with the mean value depicted as a central line. The upper and lower control limits, which are usually set at three standard deviations from the mean, are also displayed on the chart. These control limits help determine if the process is operating within acceptable limits or if there are any variations present.
The purpose of using an average chart is to assess the stability and consistency of a process over time. By tracking the average values of the variable, it becomes easier to identify any unusual patterns or trends, such as sudden shifts, cycles, or random variations. Deviations from the control limits can indicate the presence of special causes of variation, requiring further investigation and corrective actions to be taken.
Average charts are commonly used in manufacturing, healthcare, and various industries where maintaining consistent and reliable processes is crucial. They provide a visual representation of process performance, aiding in decision-making, process improvement, and quality assurance. By continuously monitoring the average values, organizations can ensure that their processes remain in control and deliver products or services that meet or exceed customer expectations.
Etymology of AVERAGE CHART
The word "average" originated from the Middle English term "average" or "averay" which meant "financial loss incurred by damage to goods at sea". This term was derived from the Old French term "avarie" which had the same meaning. Both the Middle English and Old French terms can be traced back to the Arabic word "ʿāwar" meaning "damages".
The word "chart" comes from the Middle French term "charte" or "chartre", which meant a written document or a map. This term further originated from the Latin word "charta" meaning "papyrus leaf" or "paper". The Latin word was itself derived from the Greek word "khartēs" meaning "papyrus plant".
