« Material for Lecture 6 on Thursday 1/20/11 | Main | Homework 4 »

Monday, January 24, 2011

Comments

Ji

structure:
1.three models of serial correlation
if ut not correlated with any x, it is fine, unbiased
if ut only correlate with x2t in it own equation, biased but consistent
if ut not only correlate with x2t in it own equation, but also correlates with x from previous and after equations, biased inconsistent and inefficient( since inefficient problem, makes std error smaller than real, then make t-stat and f-stat very significant, everytime you see this big t, should consider time series problem)

2. Test for auto correlation
a.steps of durbin watson test(first order)
b.reject regions, inconclusive regions, and fail to reject regions of the D-W test.
c. prove 0

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