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.
unbiasedness指的是给估计量再取均值，这个均值就是总体均值
这道题的题目是什么意思？
