I am very confused on how to work through this problem.

Exercise 12- 16. It is time to see how statistics software tests a hypothesis. Consider an estimate of life expectancy. A classmate has estimated that life expectancy worldwide is probably about seventy-two years. You will use a ttest to determine if there is a statistical difference between the classmate's estimated life expectancy and the real life expectancy. Null hypothesis H0: life expectancy = 7 1 Alternative hypothesis H A: life expectancy = 71 For this exercise you will be using the \"Human Development Index\" data set available on the student Web site at https:// edge.sagepub.com/johnson9e. The data were collected by the United Nations and used to create an index of human development in each country based on life expectancy, income, and educational attainment. Open the le and select the Life Expectancy variable. 1.You will use 71 as the test value in your hypothesis test. In other words, you will enter 71 in the statistical package t-test and test 71 against the mean of the Life Expectancy variable. Report your observed t score on the line below. Then explain whether there is a statistically signicant difference between the values and how you came to that decision. Use a 95 percent condence level (two -tailed test)