Approximately 91 % of all adults in South Korea have a cell phone. In a simple random sample of

200 adults in the United States, 171 owned cell phones. Is there convincing evidence to suggest the

proportion of adults who own cell phones in the U.S. is lower than the proportion of adults who own

cell phones in South Korea?

(a) Conduct a significance test using the 5 step process.

(b) A 95% confidence interval for p is 0.8062 to 0.9038. Explain how this interval gives results

consistent with the test in part a.