Consider the following returns and states of the economy for TZ.Com.: Economy Probability Return Weak 15% -2% Normal 50% 3% Strong 35% 8% What is the standard deviation of TZ's returns? SET YOUR CALCULATOR TO FOUR DECIMAL PLACES AND ROUND TO 2 DECIMAL PLACES AT THE END. DO NOT ENTER THE %. FOR EXAMPLE, IF YOUR ANSWER IS 7.70% ENTER IT AS 7.70