Back to 8.3 A Confidence Interval for A Population Proportion

8.3 Exercise 55

Avg difficulty 2.5


Use the following information to answer the next two exercises: Five hundred and eleven (511) homes in a certain southern California community are randomly surveyed to determine if they meet minimal earthquake preparedness recommendations. One hundred seventy-three (173) of the homes surveyed met the minimum recommendations for earthquake preparedness, and 338 did not.

A national survey of 1,000 adults was conducted by Rasmussen Reports. It concluded with 95% confidence that 49% to 55% of Americans believe that big-time college sports programs corrupt the process of higher education.

  1. Find the point estimate and the error bound for this confidence interval.
  2. Can we (with 95% confidence) conclude that more than half of all American adults believe this?
  3. Use the point estimate from part a and n = 1,000 to calculate a 75% confidence interval for the proportion of American adults that believe that major college sports programs corrupt higher education.
  4. Can we (with 75% confidence) conclude that at least half of all American adults believe this?

OpenStax Introductory Business Statistics 2e, 8.3 A Confidence Interval for A Population Proportion, exercise 55

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Adapted from Introductory Business Statistics 2e © 2023 Rice University. Licensed under CC BY 4.0. Source: Introductory Business Statistics 2e. Imported at revision 50ec917.