Final answer:
Replication with extension is a research method used to improve external validity by repeating a study with a new sample and adding additional measures. It helps validate and verify original research findings.
Step-by-step explanation:
Replication with extension is a research method used to improve external validity. It involves replicating a study by repeating the original experiment with a new sample or population, and extending the study by incorporating additional measures or variables to expand on the original findings.
Replication with extension is important because it helps to validate and verify the original research findings. By replicating the study with different samples or populations, researchers can determine the reliability and generalizability of the results. The addition of new measures or variables also allows for a more comprehensive understanding of the phenomenon under investigation.