Answer:
a) Potential Sources of confounding:
1) Pancreatic cancer patients were being compared with persons hospitalized for cancerous diseases. Coffee may likely aggravate the pains of pancreatic cancer patients unlike other cancer patients because the latter's cancer diseases were not digestive.
2) Unintended bias was introduced by investigators in questioning patients. The investigators asked questions on coffee drinking habits of those already hospitalized. This biased the drinking of coffee as a predisposing factor.
3) There could be differences among men and women because of other habits. While drinking more coffee predisposed women to cancer, according to the confounding statements, drinking even more did not have much difference in men.
Step-by-step explanation:
"CRITICS SAY COFFEE STUDY WAS FLAWED" was an article in New York Times written by Harold M. Schmeck Jr. on June 30, 1981. It attempted to critique the study of drinking coffee and its disposal to cause cancer to the drinkers.
In this article, he introduced the views of critics of the Coffee Study which was earlier published in the New England Journal of Medicine and the accompanying refutal by the researchers.