Which of the following best describes a confounding variable's effect?

A confounding variable is an external influence that can change the effect of a dependent and independent variable. Its presence can obscure or distort the true relationship being studied, leading to misleading conclusions. When a confounding variable is present, it can appear as if the independent variable is influencing the dependent variable, when in reality, it is the confounding variable that is contributing to the observed effect.

For instance, in an experiment designed to measure the impact of a new teaching method on student performance, a confounding variable could be the prior knowledge of the students. If some students already have a high level of understanding in the subject due to outside tutoring, it might seem like the new teaching method is ineffective, masking the true relationship between the method and student performance. Thus, the answer correctly identifies that a confounding variable masks the true relationship between the independent and dependent variables, making it difficult to draw accurate conclusions from the data collected in the experiment.