conditional mean meaning in English

条件均值
条件平均数

Then we give the necessary and sufficient condition under which the optimally weighted ls estimate is identical to thu conditional mean of the parameter given input and observation , i . e . , the optimally weighted ls estimate could be optimal nonlinear estimate in the minimum variance sense
在方差阵可逆的条件下，我们发现最优加权最小二乘估计优于线性最小方差估计，进而得到了其与最小方差估计(即条件均值估计)等价的充要条件。