The Gallup Poll Correctly Predicted George H

Multiple Choice

The Gallup Poll correctly predicted George H. W. Bush's 1988 victory using only 4,089 interviews. Why, then, did the Gallup Poll in 1948 wrongly predict Dewey's victory over Truman when they used 50,000 interviews to make the prediction?

A) They only interviewed people in one state
B) They used multistage cluster sampling
C) They used quota sampling
D) They used random sampling