A survey was given to a random 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 64%. The margin of error for the survey was 3%. Write a confidence interval for the percentage of the population that supports Candidate A.
Q. A survey was given to a random 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 64%. The margin of error for the survey was 3%. Write a confidence interval for the percentage of the population that supports Candidate A.
Understand Confidence Interval: Understand the concept of a confidence interval. A confidence interval gives a range of values within which we can say with a certain level of confidence that the true population parameter lies. In this case, we are looking for the range of percentages within which the true support for Candidate A lies, given a margin of error.
Calculate Lower Bound: Calculate the lower bound of the confidence interval.To find the lower bound, subtract the margin of error from the given percentage.Lower bound = 64%−3%=61%
Calculate Upper Bound: Calculate the upper bound of the confidence interval.To find the upper bound, add the margin of error to the given percentage.Upper bound = 64%+3%=67%
Write Confidence Interval: Write the confidence interval.The confidence interval is expressed as (lower bound,upper bound). Therefore, the confidence interval for the percentage of the population that supports Candidate A is (61%,67%).
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