Question

Let X be a discrete random variable assuming values x₁, x₂, ..., x_n with probabilities p₁, p₂, ..., p_n, respectively. Then variance of X is given by ______.

Options

• E(X²)

• E(X²) + E(X)

• E(X²) – [E(X)]²

• `sqrt("E"("X"^2) - ["E"("X")]^2)`

Answer 1

Let X be a discrete random variable assuming values x₁, x₂, ..., x_n with probabilities p₁, p₂, ..., p_n, respectively. Then variance of X is given by E(X²) – [E(X)]².