Correct Answer: D
A run chart, also known as a run-sequence plot, is a basic tool for analyzing data over time.
* Process Stability:
* Stability is analyzed using the run chart, but it is not an essential element of the chart itself.
* Defect Classifications:
* While defects can be plotted, they are not essential to all run charts.
* Special Causes:
* Identifying special causes can be an outcome of analyzing a run chart, but it is not an essential element.
* Time Sequence:
* The essential element of a run chart is the time sequence. It plots data points in time order to show trends, shifts, or cycles.
* This temporal plotting helps in understanding how the process changes over time.
References: Statistical process control literature and quality management resources discussing run charts.