4. s ndvridend) of a share of stock is randomly distributed with 5 different mes possible as listed in the table below he return( x,:return f(x)-probability 10 15 18 30 0.25 0.35 0.20 0.15 0.05 Calculate the following: a. x) (the population mean) (the population variance) (the population standard deviation) An investor buys the stock and over the next 25 years (N-25) the investor earns an annual average return of 7.5. The investor decides to sell the stock if the probability of earning an average return less than or equal to 7.5 is less than 10%. d. what is the probability of Fs 7.5 given N-25 and the E(x) and r as calculated above? Should the investor sell? (Hint: use the z-variable and table) What is the probability of the stock earning an average return greater than 11 given N-25 and the E(x) and ii. as calculated above? ii What is the probability of earning an average return between 7.5 and 11 given N-25 and the E(x) and as calculated above