The United Nations wants to know how long future wars the in world are going to last. Years of research has shown that typical war has a mean duration of 4 years and a standard deviation of 2.5. You look at the duration of wars in Africa (20 wars) in the last year and observe a mean of 4.7. Use the formulas & X + Z, *6-, to calculate standard error and the confidence intervals respectively, for the following (6 points each) 13) Calculate the standard error of the mean: 14) Calculate the 95% confidence interval