Investment and Corresponding Returns
Scenario	Probability	Project A	Project B	Project C	Project D
Pessimistic	50%	-8%	-5%	-7%	0%
Normal	40%	0	1%	-2%	1%
Optimistic	10%	5%	3%	6%	2%

what is the standard deviation?

with the values of Expected Return for Project A -3.50%

Expected Return for Project B -1.80%

Expected Return for Project C -3.70%

Expected Return for Project D 0.60%