1
CHAPTER 18 SECTION 1: MODEL BUILDING
MULTIPLE CHOICE
1. The model
y
=
β
0
+
β
1
x
1
+
β
2
x
2
+
β
3
x
1
x
2
+
ε
is referred to as a:
a.
firstorder model with two predictor variables with no interaction.
b.
firstorder model with two predictor variables with interaction.
c.
secondorder model with three predictor variables with no interaction.
d.
secondorder model with three predictor variables with interaction.
ANS: B
PTS: 1
REF: SECTION 18.1
2. The model
y
=
β
0
+
β
1
x
+
β
2
x
2
+
.........
+
β
p
x
p
+
ε
is referred to as a polynomial model with:
3.
For the following regression equation
y
8
=
20
+
8
x
1
+
5
x
2
+
3
x
1
x
2
, which combination of
x
1
and
x
2
,
respectively, results in the largest average value of
y
?
4.
For the following regression equation
y
8
=
50
+
10
x
1

4
x
2

6
x
1
x
2
, a unit increase in
x
2
, while holding
x
1
constant at a value of 3, decreases the value of
y
on average by:
5.
Suppose that the sample regression line of the firstorder model is
y
8
=
8
+
2
x
1
+
3
x
2
. If we examine the
relationship between
y
and
x
1
for four different values of
x
2
, we observe that the:
a.
effect of
x
1
on
y
remains the same no matter what the value of
x
2
.
b.
effect of
x
1
on
y
remains the same no matter what the value of
x
1
.
c.
only difference in the four equations produced is the coefficient of
x
2
.
d.
Cannot answer this question without more information.
ANS: A
PTS: 1
REF: SECTION 18.1
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6.
Suppose that the sample regression equation of a secondorder model is given by
y
8
=
2.50
+
0.15
x
+
0.45
x
2
. Then, the value 4.60 is the:
7.
For the following regression equation
y
8
=
75
+
20
x
1

15
x
2
+
5
x
1
x
2
, a unit increase in
x
2
, while holding
x
1
constant at 1, changes the value of
y
on average by:
8.
For the following regression equation
y
8
=
100

12
x
1
+
5
x
2

4
x
1
x
2
, a unit increase in
x
1
, while holding
x
2
constant at a value of 2, decreases the value of
y
on average by:
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 Spring '10
 Kumar
 Linear Regression, Regression Analysis, pts, REF

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