作者bcs (= ="frailty..gggg XD)
看板Economics
標題[請益] 計量的causality
時間Sat Oct 17 14:44:22 2009
出處:
http://tinyurl.com/ykbawo6
reg lines from economic data often cannot be given a causal interpretation.
The reason being that in the relation of interest between observables
and unobservables we might expect they are correlated, whereas in a
^^^^^^^^^^^^
reg model regressors and unobservables are uncorrelated by construction.
請問黃字文意為何?
y=xb+e
迴歸假設之一： E[xe]=0 為了得到b的認定.
不懂的是為何 E[xe]!=0 會是expect的條件為了casuality的關係？
謝謝^^"
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※ bcs:轉錄至看板 Statistics 10/17 14:45
1F：推 JamesChen:Non stochastic 也可以解釋 10/17 15:06
2F：推 ichibond3:我記得greene的附錄c有證明 10/19 20:14