Step 1 :Given the confidence interval for a population mean is \(12.13<\mu<12.73\).
Step 2 :The margin of error (E) in a confidence interval is calculated as the difference between the upper limit and the mean or the difference between the mean and the lower limit.
Step 3 :In this case, the mean (\(\mu\)) is not given directly, but it can be calculated as the average of the lower and upper limits of the confidence interval.
Step 4 :Calculate the mean (\(\mu\)) as \((12.13 + 12.73) / 2 = 12.43\).
Step 5 :Once we have the mean, we can subtract it from the upper limit or add it to the lower limit to get the margin of error.
Step 6 :Calculate the margin of error (E) as \(12.73 - 12.43 = 0.30\).
Step 7 :Final Answer: The margin of error, \(E\), is \(\boxed{0.30}\).