Chapter 18.2, Problem 1JC

Every 10 years, the United States takes a census. The census tries to count every resident. There have been two forms, known as the “short form,” answered by most people, and the “long form,” slogged through by about one in six or seven households chosen at random. (For the 2010 Census, the long form was replaced by the American Community Survey.) According to the Census Bureau (www.census.gov), “. . . each estimate based on the long form responses has an associated confidence interval.”

1. Why does the Census Bureau need a confidence interval for long-form information but not for the questions that appear on both the long and short forms?