October 24, 2008
Econometrics Midterm I
ARE 106
Havenner
Three questions on two pages. Use 5% significance levels unless otherwise indicated. Closed book.
Answer all questions. Bracketed values are points for the questions. Note that the last question has
62 'points in total.
The following formulas
mayor may not be of use:
For any random variables Y and Z:
Cov(Y,Z)
=E[Y
E(Y)]
[Z
E(Z)] Corr(Y,Z)
=
Cov (Y,Z)/[""Var(Y) ""Var(Z)]
P(Y

tAlZ,n
zSf
$,
E (Yo)
$,
Y
+
tAlZ,n
z Sf)
=
1 
A
where
A
is the statistical significance level
For the simple linear regression model analyzed in class:
A
~XjX)(YjY)
Z
c,z
(,z
(3=
~Xj_X)2'
S~
=
~xjxf'=='s.a
n
Z
A
Z
AZ
S
==
0
=
LUi I (n
 2)
i=1
i
I
I
I
I
1.
As you know from the class notes (pages 5be) there has been aconjecture that exposure to florescent
lights causes skin cancer. A small US study noted that office workers often develop skin cancer, and
a much larger UK study found the correlation between hours of exposure to florescent lighting and
developing skin cancer to be large and statistically significant. Does this convince you that florescent
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.