12. Given the following discrete probability distribution, x P(x) 420.375 65 0.15 700.225 75 0.05 90 0.2 (a). Calculate the expected value of x. (b). Calculate the variance of x. (c). Calculate the standard deviation of x. 16.The returns on shares of company A and B vary depending on the state of economic growth. Probability Return on A Return on B State of the economy P. RA (%) Rg (%) Boom 0.3 20 3 Growth 0.4 10 35 Recession 0.3 0 -5 a). Calculate expected return and standard deviation of company A shares. (2 marks) b). Calculate expected return and standard deviation of company B shares. (2 marks) C). What are the covariance and the correlation coefficient between returns on A and returns on B? (1 mark)