Further question on this explanation: Where did you get this calculation: Risk is the Standard deviation = (10%²)^1/2 = 3.1623 or 3.16%

Explanation:

Probability(P) Return(X) PX X-Mean P(X-Mean)^2 0.05 10 0.5 -10 5 0.90 20 18 0 0 0.05 30 1.5 10 5 Expected Return/Mean 20 10 

Risk is the Standard deviation = (10%²)^1/2 = 3.1623 or 3.16%

Co-efficient of Variation = (SD / Mean) * 100 = (3.1623 / 20) * 100 = 15.8114 or 15.81