2. The average age at death in a certain country is 75 years, With a standard deviation of 10 years. Researchers believe the average age at death of the country's indigenous population is signicantly lower. A random sample of 50 records gives a sample mean of 72.4 years as the age at death for the country's indigenous population. (a) Form an appropriate null and alternative hypothesis for this study. (b) Find the zstatistics value. (c) Sketch a Standard Normal curve, post the z-statistics value on it. (d) Are the results signicant at the 5% level? Write your conclusions in the context of the