In COPTR analyses, what is a confounding variable and how can it bias results?

• A. A confounding variable is a measurement error that occurs randomly.
• B. A confounding variable is related to both the exposure and outcome, creating spurious associations; control via design or statistics.
• C. A confounding variable is irrelevant to the study outcomes.
• D. A confounding variable is a type of data visualization technique.

Answer: (B)