Which type of Control Chart should be used to monitor the diameter of a pipe?

The choice of a Variables Control Chart is appropriate for monitoring the diameter of a pipe because it involves continuous data that can take on a range of values. Control charts for variables are specifically designed to track quantitative measurements, which can provide insights into the variability and process stability over time. Since the diameter of a pipe is a measurable characteristic that can be expressed in numerical terms (e.g., inches or millimeters), a Variables Control Chart allows for precise monitoring and helps identify any trends, shifts, or out-of-control conditions in the manufacturing process.

On the other hand, Attribute Control Charts are used for data that categorizes items into discrete classifications (e.g., pass/fail, defective/non-defective). Since pipe diameter is not a binary measurement but rather a continuous variable, this type of chart would not be suitable for accurately assessing the process capability or performance related to dimensional measurements. Thus, for monitoring measurements like the diameter of a pipe, utilizing a Variables Control Chart is the proper approach.