The variance of a discrete random variable is defined as Var(X) = E[(X - mμ)²] , which in turn is defined as Var(X) = σ²ₓ = sumlimits (xᵢ) - muₓ)²pᵢ. The standard deviation of a discrete random variable is the square root of the variance. σₓ = SD(X) = √Var(X)

Use the equation shown in the margin to calculate Var(G), the variance of the number of green lights that Nicholas encounters.