Young's modulus is a quantitative measure of stiffness of an elastic material. Suppose that for metal sheets of a particular type, its mean value and standard deviation are 70 GPa and 2.2 GPa, respectively. Suppose the distribution is normal. (Round your answers to four decimal places.) I USE SALT (a) Calculate P(69 X 71) when n = 9. (b) How likely is it that the sample mean diameter exceeds 71 when n = 16? You may need to use the appropriate table in the Appendix of Tables to answer this question.