A.
(A) 该估计器的性能始终满足\(\min (\frac{{{\sigma ^2}}}{N},\sigma _A^2) < MSE(\hat A) < \max (\frac{{{\sigma ^2}}}{N},\sigma _A^2)\)
B.
(B) 对任意一组给定的观测值,\(min ({\mu _A},\bar z) \le \hat A \le \max ({\mu _A},\bar z)\)始终成立
C.
(C) 对一组给定的观测值,\(\frac{{{\sigma ^2}}}{N} < \sigma _A^2\)时,\(\left| {\hat A - \bar z} \right| < \left| {\hat A - {\mu _A}} \right|\)
D.
(D) 对一组给定的观测值,当\(\frac{{{\sigma ^2}}}{N} > \sigma _A^2\)时,\(\left| {\hat A - \bar z} \right| < \left| {\hat A - {\mu _A}} \right|\)