6 Suppose we want to test the theory of economic voting which attempts to connect the idea that the state of the economy (X) affects an incumbent president's vote share (Y). Suppose I claim that X causes Y. Provide a convincing answer to each of the four questions on hurdles of causality listed below. Is there a credible causal mechanism connecting X and Y? Can you rule out the possibility that Y causes X? Do X and Y covary, how? Are there any confounding Z variables that would make the relationship between X and Y spurious? What variables would you need or want to control for in a model predicting presidential vote share? (i.e. what other factors might be important to predicting vote share besides the economy?)