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Stat 155–Probability and Statistics for Science and EngineeringSecond Mid-Term ExaminationMay 21, 2018Multiple Choice Questions (5 points each). Please choose theSINGLEbest answer and indicateyour choice on the scantron.1.Exhibit I.Suppose the random variableXhas the following probability mass function (pmf):x-102p(x)0.20.60.2The expected value ofXis(a) 0(b) 0.2(c) 0.4(d) 0.6(e) none of the above2. Refer to Exhibit I. The variance ofXis3. Refer to Exhibit I. LetF(x) be the cumulative distribution function (cdf) ofX. Which ofthe following statements istrue?4. A geologist has collected 10 specimens of basaltic rock and 10 specimens of granite. The geol-ogist instructs a laboratory assistant to randomly select 15 (different) specimens for analysis.LetXbe the number of granite samples selected for analysis. What is the distribution ofX?1