Exercise Questions: Chapter 10
10.1
Understanding a linear regression model.
Consider a linear regression model with
μ
y
=
40.5  2.5
x
and standard deviation
= 2.0.
(a) What is the slope of the population regression line?
(b) Explain clearly what this slope says about the change in the mean of
y
for a change in
x
.
(c) What is the subpopulation mean when
x
= 10?
(d) Between what 2 values would approximately 95% of the observed responses,
y
, fall
when
x
= 10?
10.7
What’s wrong?
For each of the following, explain what is wrong and why.
(a) The parameters of the simple linear regression model are
b
0
,
b
1
, and
s
.
(b) To test
H
0
:
b
1
= 0, use a
t
test.
(c) For a particular value of the explanatory variable
x
, the confidence interval for the
mean response will be wider than the prediction interval for a future observation.
10.13
Beer and blood alcohol.
How well does the number of beers a student drinks
predict his or her blood alcohol content? Sixteen student volunteers at Ohio State
University drank a randomly assigned number of 12ounce cans of beer. Thirty minutes
later, a police officer measured their blood alcohol content (BAC). Here are the data:
9
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 Spring '11
 erick
 Linear Regression, Regression Analysis, Standard Deviation, linear regression model, blood alcohol, population regression line

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