B draw a directed acyclic graph dag indicating under

b. Draw a directed acyclic graph (DAG) indicating under what
potential circumstances confounding by income give rise to a
crude measure of association between distance to major roadway
and myocardial infarction that is HIGHER in absolute value than the
true value (either over-estimating a harmful effect or
underestimating a protective effect).

c. If income is not truly associated with distance to major roadway in
the study base, but is associated with MI, would you expect that
adjusting for income would change the point estimate of the
association of distance to a major roadway with MI?
2. A study aims to investigate the association between obesity and
incidence of coronary heart disease.
a. Given an example of confounder that needs to be accounted for
and justify your choice.
b. Draw a DAG to depict the scenario. Use (+) and (-) signs to depict
the direction of the association between the variables.
c. The investigators chose to adjust for low-density
lipoprotein cholesterol level. Do you agree with them? Just your
answer using DAG.