b. Draw a directed acyclic graph (DAG) indicating under whatpotential circumstances confounding by income give rise to acrude measure of association between distance to major roadwayand myocardial infarction that is HIGHER in absolute value than thetrue value (either over-estimating a harmful effect orunderestimating a protective effect).
c.If income is not truly associated with distance to major roadway inthe study base, but is associated with MI, would you expect thatadjusting for income would change the point estimate of theassociation of distance to a major roadway with MI?2. A study aims to investigate the association between obesity andincidence of coronary heart disease.a. Given an example of confounder that needs to be accounted forand justify your choice.b.Draw a DAG to depict the scenario. Use (+) and (-) signs to depictthe direction of the association between the variables.c. Theinvestigators chose to adjust for low-densitylipoprotein cholesterol level. Do you agree with them? Just youranswer using DAG.