According to "Assessing the Validity of the PostMaterialism Index" (American
Political Science Review [1999]: \(649-664\) ), one may be able to predict an
individual's level of support for ecology based on demographic and ideological
characteristics. The multiple regression model proposed by the authors was
$$
\begin{aligned}
&y=3.60-.01 x_{1}+.01 x_{2}-.07 x_{3}+.12 x_{4}+.02 x_{5} \\
&\quad-.04 x_{6}-.01 x_{7}-.04 x_{8}-.02 x_{9}+e
\end{aligned}
$$
where the variables are defined as follows
\(y=\) ecology score (higher values indicate a greater con-
$$
\begin{aligned}
& \text { cern for ecology) } \\
x_{1}=& \text { age times } 10
\end{aligned}
$$
\(x_{2}=\) income (in thousands of dollars) \(x_{3}=\) gender \((1=\) male, \(0=\)
female \()\) \(x_{4}=\) race \((1=\) white, \(0=\) nonwhite \()\) \(x_{5}=\) education (in
years) \(x_{6}=\) ideology \((4=\) conservative, \(3=\) right of center, \(2=\) middle
of the road, \(1=\) left of center, and \(0=\) liberal \()\) \(x_{7}=\) social class
\((4=\) upper, \(3=\) upper middle, \(2=\) middle, \(1=\) lower middle, \(0=\) lower \()\)
\(x_{8}=\) postmaterialist ( 1 if postmaterialist, 0 otherwise) \(x_{9}=\)
materialist \((1\) if materialist, 0 otherwise)
a. Suppose you knew a person with the following characteristics: a 25-year-
old, white female with a college degree (16 years of education), who has a \(\$
32,000\) -per-year job, is from the upper middle class and considers herself
left of center, but who is neither a materialist nor a postmaterialist.
Predict her ecology score.
b. If the woman described in Part (a) were Hispanic rather than white, how
would the prediction change?
c. Given that the other variables are the same, what is the estimated mean
difference in ecology score for men and women?
d. How would you interpret the coefficient of \(x_{2}\) ?
e. Comment on the numerical coding of the ideology and social class variables.
Can you suggest a better way of incorporating these two variables into the
model?
