Problem
A survey was given to a randorn sample of voters in the United States to ask about their preference for a presidential candidate. The percentage of people who said they preferred Candidate A was $55 \%$. The margin of error for the survey was $3.5 \%$. Write a confidence interval for the percentage of the population that supports Candidate A.
Solution
Step 1 ：Given percentage: \(55%\) and margin of error: \(3.5%\)
Step 2 ：Calculate lower bound: \(55 - 3.5 = 51.5%\)
Step 3 ：Calculate upper bound: \(55 + 3.5 = 58.5%\)
Step 4 ：\(\boxed{Confidence\ Interval: (51.5%, 58.5%)}\)
