9. Independently toss a fair dice 4 times. Suppose that Xᵢ is the outcome of the iᵘ toss, and X̄ = (X₁ + X₂ + X₃ + X₄) / 4. Then Var(X̄) is:
(A) \( \frac{35}{12} \)
(B) \( \frac{35}{24} \)
(C) \( \frac{35}{36} \)
(D) \( \frac{35}{48} \)
(E) \( \frac{35}{60} \)

答案:登入後查看
統計: 尚無統計資料