A confidence interval for a population mean has a margin of

A confidence interval for a population mean has a margin of error of 4.

a) Determine the length of the confidence interval.

b) If the sample mean is 53.6, obtain the confidence interval.
Confidence interval:

Solution

a) Length = 2*ME = 8

b) CI = x-bar +/- ME = (49.6, 57.6)