Which of the following is true for the standard deviation σ\sigmaσ and variance σ2\sigma^2σ2?
σ=σ2\sigma = \sigma^2σ=σ2
σ=Var(X)\sigma = \sqrt{Var(X)}σ=Var(X)
σ=Var(X)2\sigma = Var(X)^2σ=Var(X)2
σ=Var(X)/2\sigma = Var(X)/2σ=Var(X)/2