A confounding variable is an outside influence that can affect the results of an experiment or study. It can create a false impression of a relationship between the main variables being studied. For example, if researchers are examining the effect of exercise on weight loss, a confounding variable could be diet. If participants eat differently, it may skew the results, making it hard to determine if exercise alone is responsible for weight loss. To accurately understand the relationship between variables, researchers must identify and control for confounding variables. This ensures that the results reflect the true effects of the main variables, like exercise and weight loss, without interference from other factors.