NO.PZ2017092702000109
问题如下：
An estimator with an expected value equal to the parameter that it is intended to estimate is described as:
选项：
A. efficient.
B. unbiased.
C. consistent.
解释：
B is correct.
An unbiased estimator is one for which the expected value equals the parameter it is intended to estimate.
如题、不懂为什么不选一致性
