What sample size should be used if we would like to estimate the mean age of the college students at a particular campus with 95% confidence? We would like to be accurate to within three years, and we...

What sample size should be used if we would like to estimate the mean age of the college students at a particular campus with 95% confidence? We would like to be accurate to within three years, and we will assume the population is normally distributed with a standard deviation of 5.1 years.