Final answer:
Investigators repeat an experiment to confirm the validity and reliability of findings.
Step-by-step explanation:
Investigators sometimes repeat an experiment that other researchers have already completed to confirm the validity and reliability of findings. By replicating the experiment, scientists can determine if the results are consistent and can be trusted. This helps to ensure that the original research is accurate and can be relied upon by other scientists. It is an important step in the scientific method to verify and validate findings through replication.