Ry $S$ stock returns have the following probability distributions:

$\backslash$table$[[,$Yields$],[$Probability$,$Action R$,$Action S$],[0\mathrm{.}5,-2\%,12],[0\mathrm{.}1,10,2],[0\mathrm{.}4,15,12]]$

a$.$ Calculate the expected return on each stock.

b$.$ Calculate the standard deviation of the returns for each stock and for the portfolio. Which action is considered riskiest with respect to the total risk?

c$.$ Calculate the coefficient of variation for each stock. Based on the coefficient of variation, which stock is considered riskier?