Assignment #11

PPol 604

Due: Thursday, 4 April 2013

Type up your answers. Give proper credit to those you work with and/or the text(s).

Solve the following problems. Show all of your work, but keep your answers concise. Highlight your (final) answer to distinguish it from your other numbers and text. Include a copy of your input (e.g. do file) or output (e.g. log file), when it is an appropriate way to show your work. However, do not include unnecessary output (i.e. no data dumps), and format any output so that it is easily readable. An appropriate time to include output is when you put your results in a table--if your results are wrong, then the grader has no idea how you came to your conclusions (i.e. give partial credit) unless you provide some output. Explanation includes statistical and substantive explanation (explain so that a statistical layperson can understand it, and so that a statistical analyst will see your erudition).

1. {20} Rabe-Hesketh and Skrondal 8.4. In step 3, interpret the intraclass correlation. Add the following part:
   • 5. Using the model of step 2, compare the substantive significance of edyears and income. (Policy question: Should we utilize resources encouraging education or boost income?) Calculate the baseline probability of survival at the end of the observation period (60 months) setting all variables to their medians. Then increase edyears to the 95th percentile and calculate the probability of survival. After returning edyears to its median, increase income to its 95th percentile and calculate the probabilty of survival. Where should resources be allocated? [Note: for xtcloglog, the command is predict newvar, pu0]
2. {30} Rabe-Hesketh and Skrondal 8.1. In step 2, compare using AIC/BIC as well. Add the following part:
   • 7. Using the quadratic model of step 2, compare the substantive significance of art and prestige. Calculate the baseline median survival time setting all variables to their means (except phdmed set to 0). Then increase art by 2 (between) standard deviations, and calculate the median survival time. Then (returning art to its mean) decrease prestige by 2 (between) standard deviations, and calculate the median survival time. Which variable has the stronger effect? [Why increase one and decrease the other?]
3. Work on your poster.

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