Long-Term Effects of 9/11 on the Political Behavior of Victims’ Families
Long-Term Effects of 9/11 on the Political Behavior of
Victims’ Families
In this exercise, we examine a hypothesis that individuals who lost someone in the terrorist attacks of 9/11,
whether a family relative or a neighbor, will have become more politically engaged.
This exercise is based on: Hersh, E. D. 2013. “Long-Term Effect of September 11 on the Political Behavior of
Victims’ Families and Neighbors.” Proceedings of the National Academy of Sciences 110(52): 20959–63.
We will examine this hypothesis using several different estimation techniques, focusing throughout on the
effect of the attacks on the victims’ families rather than their neighbors. The CSV data file, victims9-11.csv,
contains the following variables:
Name Description
voter.id Unique identifiers of relatives and neighbors of the victims
treatment Families and neighbors of actual victims (1) vs control group (0)
victim.status Families (2) vs neighbors (3) of victims and controls
ge20xx Voting in the 20xx general election (Y=at the polls, A=absentee, E=early,
M=by mail)
fam.members Number of family members living with voter at their address
age Voter’s age
party Voter’s party affiliation (D=Democrat, R=Republicans, N=no affiliation)
sex Voter’s sex
pct.white Proportion of non-Hispanic white voters living on the same block
median.income Median income of voters living on the same block
Voters were included in the data on the basis of their relationship to actual victims – these constitute the two
treatment groups – or if no such relationship existed but they were, otherwise, sufficiently similar to voters in
the treatment groups – this constitutes the control group.
Question 1
Test the following hypothesis: In a comparison of individuals, people who have relationships with 9/11 victims
are more likely to be politically engaged than those who do not have relationships with 9/11 victims. Hint:
Feel free to recode different types of voting (i.e. Absentee, Mail, Early, At the Polls) into a dichotomous
measure (Voted = “Yes”; Not voted = “No”).
A. Describe your results
B. Use proper inferential test to estimate whether voting differed between treatment and control group for
each election year.
C. Create a graph that best visualizes group differences and most importantly justify your reasons for selecting
this particular graph.
Question 2
To what extent is the treatment suffer from selection bias? In particular, are 9/11 victims more likely to have
higher median income (median.income) and come from white neighborhoods (pct.white)? For this question,
only use voting from the 2004 general election (ge2012). Hint: the DVs are now income and percentage of
white voters on same block.
1
http://dx.doi.org/10.1073/pnas.1315043110
http://dx.doi.org/10.1073/pnas.1315043110
A. Describe your results
B. Use proper inferential test to estimate whether income and neighborhood demographics different between
treatment and control groups in the 2004 general election.
Questions 3
What is the preferred mythical beast: unicorns or gruffalos? You have two samples. In sample 1, 53% of
children preferred unicorns (n = 500) In sample 2, 58% of children preferred unicorns (n = 200). You can
assume these data are normally distributed. The debate between unicorns and gruffalos is timeless, and
children’s opinions vary (σ = 7.3 percentage points).
A. Calculate the standard error for each sample.
B. Calcuate the 95% confidence intervals of each sample.
C. Using these two samples and a two-sample test of proportions, do children’s preference for unicorns
significantly differ from their preference of gruffalos? Please explain and show your work.
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Question 1
Question 2
Questions 3