单选题设总体X～N（0，σ^2），X1，X2，…，Xn，是来自总体的样本，<img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/23817936_0.png">则下面结论中正确的是（　　）。<br/> <img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20251103/23817936_0_1.png">