you are interested in estimating the mean age of the citizens living in your community. in order to do this, you plan on constructing a confidence interval; however, you are not sure how many citizens should be included in the sample. if you want your sample estimate to be within 3 years of the actual mean with a confidence level of 94%, how many citizens should be included in your sample? assume that the standard deviation of the ages of all the citizens in this community is 21 years.