7. Complete the table below and use the results to answer the following questions (see page 190). p(x) xp(x) x2 p(x ) ( x -14 ) ( x - 14 ) ? ( x - 14 ) 2 p ( * * ) 0 0.20 2 0.60 4 0.20 Total Exp(x) [x2 p(x) E(x - 1) - P(x) a. Use this formula to calculate the expected value (mean) of the random variable x: u = Exp(x) b. Use this formula to calculate the variance of the random variable x: 62 = [x2 p( x ) - 12c. Use this formula to find the variance of the random variable x: 02 =Z(x#}2 pm. d. Which one of the formulas do you prefer and why