Mathematics · Estimation Theory

Let X1, X2, ..., Xn (n ≥ 2) be a random sample from a continuous distribution with the probability density function: f(x | θ) = (1/(2θ)) e-|x-θ|/θ, x ∈ R where θ (> 0) is an unknown parameter. Let Un = (1/n) ∑i=1n Xi, Vn = (1/n) ∑i=1n Xi2, and Sn2 = (1/(n-1)) ∑i=1n (Xi - Un)2. Then, which of the following statements is true?