the following summary of a statistical study gives a sample statistic and a margin of error. find the confidence interval.

a poll is conducted the day before a state election for senator. there are only two candidates running for this office. the poll results show that 57% of the voters favor the republican candidate, with a margin of error of 4 percentage points. what is the confidence interval?

1 answer

The confidence interval can be calculated by adding and subtracting the margin of error from the sample statistic.

In this case, the sample statistic is 57% and the margin of error is 4 percentage points.

To find the lower bound of the confidence interval, subtract the margin of error from the sample statistic: 57% - 4% = 53%.

To find the upper bound of the confidence interval, add the margin of error to the sample statistic: 57% + 4% = 61%.

Therefore, the confidence interval is 53% to 61%.