Fixed Design (Chosen )

Sunday, 18 August 2019

8:59 PM

10. Regression Analysis 
Properties of the Least Squares Estimators 
We noted that Yil(X/ Xi) JV(/30 + (31>0, a) 
Then, because Ei(Xi — R) 0, we can write 
sxy 
31 
sxx 
which is a linear combination of the normal random variables Yi, 
31 is normally distributed! 
Its expectation is 
Ei(Xi - Ei(Xi - + ßIXi) -R) 
E(31) 
Sxx 
+ unbiased estimator of [31 
sxx 
Similarly, its variance is Var(fil ) — 
Hence, the sampling distribution of 31 is 
sxx 
—R)2 
Term 2019 
[31 
2 
sxx 
MATH2099/2859 (Statistics) 
Dr Jia Deng 
sxx 
- Lecture g 
19/50

 

Now, we can write 
— 31k, 
i=l 
which is again a linear combination of normal r.v.'s (the Yi's and 31) 
the estimator is also normally distributed! Its expectation is 
E(30) E 
i=l 
— [31 R 
n 
i=l 
unbiased estimator of [30 
Similarly, we find Var(30) 02 1 + 
n sxx 
Hence, the sampling distribution of o is 
n sxx

 

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