a. Assume the following regression model where i Y₁ =B₁X₁1 + B₂X₁2 + €į, i = 1, ..., n iid N (0,0²), o > 0 holds true. Suppose that ΣX1X2 = 0. Show that the least squares estimators ₁ and ₂ from the multiple regression are the same as if we were to fit separate, simple regressions on X₁ and X₂.
a. Assume the following regression model where i Y₁ =B₁X₁1 + B₂X₁2 + €į, i = 1, ..., n iid N (0,0²), o > 0 holds true. Suppose that ΣX1X2 = 0. Show that the least squares estimators ₁ and ₂ from the multiple regression are the same as if we were to fit separate, simple regressions on X₁ and X₂.
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
Related questions
Question
![a. Assume the following regression model
where Ei
Y₁ = B₁1X₁1 + B₂X₁2 + €į, i=1,...,n
iid
N(0, o²), σ > 0 holds true. Suppose that
ΣX1X2 = 0.
2
Show that the least squares estimators ₁ and ₂ from the multiple regression are the
same as if we were to fit separate, simple regressions on X₁ and X₂.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F6f7fc17b-d094-4628-a31a-d218ddf517ad%2F67869420-5e0f-4f11-b86e-b4131762d2c5%2Fpmb317k_processed.png&w=3840&q=75)
Transcribed Image Text:a. Assume the following regression model
where Ei
Y₁ = B₁1X₁1 + B₂X₁2 + €į, i=1,...,n
iid
N(0, o²), σ > 0 holds true. Suppose that
ΣX1X2 = 0.
2
Show that the least squares estimators ₁ and ₂ from the multiple regression are the
same as if we were to fit separate, simple regressions on X₁ and X₂.
![b. Consider the following functions of the random variables X₁, X2, X3, and X4:
· [X1 + X2 + X3 + X4]
Y₁
=
1
Y2 = [X₁ + X2] - [X3 + X4]
2
(i) State the above in the matrix notation.
(ii) Find the expectation of the random vector Y
(iii) Find the variance-covariance matrix of Y =
= Y₂
H](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F6f7fc17b-d094-4628-a31a-d218ddf517ad%2F67869420-5e0f-4f11-b86e-b4131762d2c5%2F2leu6me_processed.png&w=3840&q=75)
Transcribed Image Text:b. Consider the following functions of the random variables X₁, X2, X3, and X4:
· [X1 + X2 + X3 + X4]
Y₁
=
1
Y2 = [X₁ + X2] - [X3 + X4]
2
(i) State the above in the matrix notation.
(ii) Find the expectation of the random vector Y
(iii) Find the variance-covariance matrix of Y =
= Y₂
H
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