A 2001 study reviewed data from a previous study of 7316 Danish adults who completed a questionnaire about their diet. They determined that there were two dietary patterns: a high-fiber diet (frequent consumption of wholemeal bread, fruits, and vegetables) and a Western diet (frequent consumption of meat products, potatoes, white bread, butter, and lard). The 2001 study found that those on a high-fiber diet have lower death rates than those on the Western diet.
a. The title of the journal article says the study is observational. Why does that make sense?
b. Explain why it would be unethical to perform an experiment about this topic.
c. Describe the sample and the population.
d. What are the explanatory and response variables?
e. What is the conclusion of the study? Does this mean there is causality or only an association between the two variables? Explain.