Find a statement which is not true. 1) The mean of a net return of certain financial asset can represent the average profitability of investment in the asset. 2) The variance (or standard deviation) of a net return of certain financial asset can represent an aspect of risk in that asset. 3) Volatility is a jargon in the finance industry, and it means the variance of a net return of certain asset. 4) There is no random variable with negative standard deviation. 5) When you know the mean and variance of a return, you can find its risk premium and volatility easily since the riskfree rate is public knowledge, and vice versa.