Final answer:
A point below the lower control limit on a range chart may suggest that process variation has decreased. However, it's crucial to investigate why this has happened to confirm it's a true improvement and not due to any errors or special causes.
Step-by-step explanation:
The question concerns a point that plots below the lower control limit on the range chart. The correct answer is E) may be an indication that process variation has decreased. Control charts are used in statistical process control to monitor the variation in processes and detect when a process is out of control. Lower process variation is usually a sign of improvement. However, any point outside the control limits, whether above or below, could indicate that something special or unusual is happening with the process that should be investigated. A point below the lower control limit can suggest a beneficial reduction in process variation, but it's essential to examine why this occurred to ensure it’s not due to data entry error, incorrect calculation of control limits, or another special cause.