The accompanying frequency distribution summarizes sample data consisting of ages of randomly selected inmates in federal prisons. Use the data to construct a 95% confidence interval estimate of the mean age of all inmates in federal prisons.

Age (years) Number 16-25 13 26-35 61 36-45 67 46-55 37 56-65 13 Over 65 6

Using the class limits of

66-75

for the "over 65" group, find the confidence interval.