(a) Calculate the crude odds ratio (for the association of coffee drinking and CAD) and the two stratum-specific odds ratios. Show your calculations. (3 pts)
(b) Next assess whether:
i. smoking is related to coffee consumption among those without CAD.
ii. smoking is related to CAD among subjects with low coffee consumption
Show the new 2×2 tables for these relationships and your calculations for the stratum specific ORs for the new tables. (4 pts)
(c) If you knew nothing else about this clinical/biological system, are the data given in the question and your calculations in item (b) sufficient evidence for you to conclude that smoking is a confounder in the relationship between coffee use and CAD? Explain the rational behind your answer.