The market and Stock J have the following probability distributions:

$\backslash$table$[[$Probability$,$r$\_($M$),$r$\_($J$)],[0\mathrm{.}3,15\%,20\%],[0\mathrm{.}4,9,5],[0\mathrm{.}3,18,12]]$

a$.$ Calculate the expected rates of return for the market and Stock J$.$

b$.$ Calculate the standard deviations for the market and Stock J$.$