The age of the father of each child is noted on the first year of primary school registration form. The following ages were observed in a sample of 16 ballots:

32 48 33 22 29 30 45 25

36 27 34 35 52 38 37 28

Estimate the mean age of all parents of first-year primary school children, using a 95% confidence interval. (Suppose the ages are normally distributed)