I need help with questions 2~6.
CSSS/SOC/STAT 321: Midterm Exam CSSS/SOC/STAT 321: Midterm Exam Due: May 14, 2021, at 11:59pm The following exam is worth 20 points towards your final grade. Your answers should be submitted on Canvas as a knitted PDF by Friday, May 14, 2021, at 11:59pm. Please write any written, non-code responses (i.e., interpretations) in the main text and not in R code chunks. You should check your PDF carefully before uploading to ensure written answers, code, and plots are visible and accurately reflect your final answers. The exam is open-book, open-note, and open-internet. However, you should not communicate with other humans about the exam. Basically, complete the assignment on your own. You are forbidden from exchanging texts/emails/chats/DMs etc. about the exam; sharing notes about the exam or the course; posting material on the internet about the exam; asking for help with a question on the exam from online forums; requesting that someone produce materials that could be helpful for the exam. If you are uncertain about whether a resource is permissible, please do not hesitate to contact me directly (
[email protected]). Background The guided analysis and questions below are based on the following paper: Green, Donald P., Tiffancy C. Davenport, and Kolby Hanson (2019). “Are There Long-Term Effects of the Vietnam Draft on Political Attitudes or Behavior? Apparently Not.” Journal of Experimental Political Science. 6(2), 71-80. This paper examines the long-term effects of the Vietnam draft lottery on the political attitudes and behavior of the men who were were eligible for the draft during the period of 1969–1971. Based on birth dates, the draft lottery was used to randomly select men who turned 19 prior to 1969, 1970 and 1971 to serve in the US army. While many of those selected did not eventually serve, the authors use a survey and publicly available information, such as voter registration, voter records and partisan membership of eligible draftees to study whether being assigned to the draft has any long-term political effects. The data set draft.csv contains the following variables obtained from surveys conducted by Green, Dav- enport, and Hanson (2019) on draft-eligible men from 2014 to 2016. Name Description draft Whether a respondent was drafted (1) or not (0) year Birth year ideology Ideology score that takes values from 1 to 5 where 1 is “very conservative,” 3 is “moderate,” and 5 is “very liberal.” state Respondent’s living state Question 1 (2 points) Create a barplot of the ideology variable with the heights corresponding to counts in each category. Format this plot nicely with axis labels and informative labels for each bar the on barplot, taking care to abbreviate the ideology category labels to have them all fit on the plot. 1 mailto:
[email protected] https://doi.org/10.1017/XPS.2018.18 https://doi.org/10.1017/XPS.2018.18 Question 2 (3 points) Create a new binary variable, liberal, that is 1 if a respondent says they are liberal or very liberal, and 0 otherwise. Use this variable to calculate the sample proportion of respondents that are liberal by the year that respondents were born in. Briefly interpret these proportions (1-2 sentences). Note: that ideology (and thus liberal) has missing values in it and you should remove those observations from any calculations. Question 3 (5 points) Events at an early stage of life can have a long-lasting impact on a person’s political perspectives. To examine whether this is true in this setting, estimate the sample average treatment effect of being drafted (draft) on ideology (liberal). Report your estimate and provide an interpretation of this result. Question 4 (5 points) Even if we assign the same treatment, respondents’ characteristics can change its effect. In this question, let’s focus on the potential for geographic heterogeneity given we have survey data from respondents residing in both Colorado and Oregon (state). Estimate the sample average treatment effect of being drafted on identifying as liberal in 2014 by respondents’ state of residence. Briefly interpret your results. Question 5 (2 points) A politician from a country in Latin America is planning to use this paper to discuss the effect of draft lottery in her country. Is this a valid approach for policy making? Discuss briefly. Question 6 (3 points) Imagine you are hired to do a statistical consulting project for a policymaker who intends to use this research design to study public heath, rather than political ideology, outcomes. In your first meeting, there is a disagreement among your clients that you are asked to resolve. One of them argues the study should use whether the respondent actually served in Vietnam as the treatment, while the other says that it should be being drafted or not. Given what you know about this setting, which of these two approaches would have higher internal validity? Explain your reasoning in 2-4 sentences. 2 Background Question 1 (2 points) Question 2 (3 points) Question 3 (5 points) Question 4 (5 points) Question 5 (2 points) Question 6 (3 points)