3. You want to estimate the average age of the students in your career. Suppose there are 130 men and 270 women and we have divided them into 2 strata: MEN AND WOMEN MAN WOMAN 20 20 18 21 22 23 21 18 22 20 20 22 19 19 18 23 22 19 21 22 Considering the men and women of the previous sample survey as subsamples of the previous strata a. Estimate the average age of the students in your major. Later Compute the expected sampling error. b. Obtain a 95% confidence interval for the mean age? What is the maximum error? c. What sample size and subsamples should I use to estimate the mean age with a maximum permissible error of 1/2 year