Your firm's analyst believes that economic conditions during the next year will be either strong, normal, or weak, and she thinks that Crary Inc.'s returns will have the probability distribution shown below. What's the standard deviation of Crary's returns as estimated by your analyst?

Economic
Conditions	Prob.	Return
Strong	30%	32.50%
Normal	40%	10.25%
Weak	30%	-15.75%