The Gallup poll in Example 6 reported that during March 2011, 60% of Americans favored offshore drilling as a means of reducing U.S. dependence on foreign oil. The poll was based on the responses of n = 1021 individuals, and resulted in a margin of error of approximately 3%. Find the approximate margin of error had the poll been based on a sample of size (a) n = 100, (b) n = 400, and (c) n = 1600. Explain how the margin of error changes as n increases.