一个有效的工具变量应满足如下两个条件
A、corr(Zi, Xi) = 0 and corr(Zi, ui) ≠ 0
B、corr(Zi, Xi) = 0 and corr(Zi, ui) = 0.
C、corr(Zi, Xi) ≠ 0 and corr(Zi, ui) = 0
D、corr(Zi, Xi) ≠ 0 and corr(Zi, ui) ≠ 0
发布时间:2025-01-20 20:51:31
A、corr(Zi, Xi) = 0 and corr(Zi, ui) ≠ 0
B、corr(Zi, Xi) = 0 and corr(Zi, ui) = 0.
C、corr(Zi, Xi) ≠ 0 and corr(Zi, ui) = 0
D、corr(Zi, Xi) ≠ 0 and corr(Zi, ui) ≠ 0