Chapter 5: SLR Assumptions Flashcards Preview

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Flashcards in Chapter 5: SLR Assumptions Deck (6)
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1
Q

SLR Assumptions:

A
  1. Linear in parameters
  2. Random sampling
  3. There is sample variation in x
  4. Zero conditional mean
      1. -> Unbiasedness of Beta0hat and Beta1hat
  5. Homoskedasticity
2
Q

SLR1 - Linear in parameters:

A

y=Beta0^1+Beta1^1*x+u

Violation:
y=Beta0^2+Beta1^2*x=u

3
Q

SLR2 - Random sampling:

A

((xi;yi):i=1,2,…,n), so yi=Beta0+Beta1*xi=ui

Violation:
Cov(ui;uj) is unequal 0 for all i unequal j

4
Q

SRL3 - There is sample variation in x:

A

Summation of (xi-xbar)^2 >0

Violation:
Summation of (xi-xbar)^2=0
5
Q

SRL4 - Zero conditional mean:

A

E(ui|xi)=0

Violation:
E(ui|xi) unequal 0.

6
Q

SRL5 - Homoskedasticity:

A

The conditional variance of u is a constant.
Var(ui|xi)=Sigma^2 (=const.)
-> Var(ui)=Sigma^2 (=const.)
-> Var(yi|xi)=Sigma^2 (=const.)

Violation:
Var(ui|xi)=Sigmai^2