this is what i have sk far. if this isnt the best way to do it, can you please show me how to do this on paper?

18. Mystery Motors, Inc. stock has the following forecasted returns for various states of the economy: State of the Economy Stock A's Return Probability 19% Recession -25% 22% -15% 25% 20% 18% 22% 16% 27% Below Average Average Above Average Boom What is the standard deviation of this stock? 18 Prob 2/31 mart 19 x -25= -4.75 1.22 x 15 -3.3 5 .25 20 = Stock 18 x 22 3.96 .16 * 27 = 4.32 Expected return=5.23 Logh || wouls 06