Final answer:
The 'control' step in DMAIC aims to maintain process improvements by monitoring and addressing variance. It mirrors experimental studies where a control group is used to isolate the effects of the independent variable being tested.
Step-by-step explanation:
The objective of the "control" step in the DMAIC process is c. To prevent an improved process from becoming highly variable again. This step is crucial to ensure that the improvements made during the DMAIC process are sustained over time. It involves implementing control systems to monitor the process and corrective actions to address any variance that may occur, sustaining the gains of the improvement efforts.
A control group in an experimental study serves as a baseline for comparison and helps in controlling for extraneous variables that might affect the results. This is essential to isolate the independent variable's effects in the experiment. The control group must be identical to the test group with the exception of the independent variable being manipulated. By doing so, researchers can determine if any observed effects are truly due to the experimental manipulation rather than other factors.