Comments on standard deviation as a measure of risk
Standard deviation (σi) measures total, or stand-alone, risk.
The larger σi is, the lower the probability that actual returns will be closer to expected returns.
Larger σi is associated with a wider probability distribution of returns.
Difficult to compare standard deviations, because return has not been accounted for.
Returns distribution for two perfectly negatively correlated projects (ρ = -1.0)
Returns distribution for two perfectly positively correlated projects (ρ = 1.0)
Illustrating diversification effects of a portfolio