試題詳解

17. Consider n samples (X1, X2,…, Xn) independently drawn from a distribution with meanμ = 0 and variance σ² = 1. The following estimator is used to estimate σ² :
  
What is the minimumn value of n that makes bias ofno greater than 0.01?
(A) 30；
(B)7；
(C) is a biased estimnator and so increasing n has no effect on reducing the bias；
(D) n does not matter here；
(E) is a biased estimator in frite sample but increasing n can reduce the bias.