A researcher was investigating whether a variable/risk factor (A) causes a particular disease (B). Upon further investigation and analysis, the researcher concluded that disease B was actually caused by another variable/risk factor (C). He concluded that C is actually a confounding variable.

a.What is a confounding variable?

b.What two conditions must variable C meet in order to be considered a confounding variable of the causal association between A and B?

c.Now, assume that variable/risk factor A actually causes C, which then causes B. What would you call (i.e. what is the terminology for describing) variable C? Explain your answer.

d.Differentiate between a mediator and an effect modifier