During the 1936 presidential election between Franklin D Roo

During the 1936 presidential election between Franklin D. Roosevelt and Alf Landon, the Literary Digest received 2.3 million mail-in ballots that it used to predict the results: a landslide in favor of Landon. Clearly, there has never been a President Landon, so the prediction was incorrect. Why?

a. the survey was subject to nonresponse bias.

b. a sample taken only from Literary Digest readers would not necessarily represent the views of the American public in general.

c. all of the answers are correct.

d. the survey relied on voluntary responses, which would introduce a bias.

Solution

OPTION C: All of the answrers were correct.

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All those who responded/not responded have their reasons, and that would introduce some bias. Also, obviously now, sample taken only from Literary Digest readers would not necessarily represent the views of the American public in general, as Landon did not win.