Lesson 18: Forecasting the 2017 Virginia Governor’s Race

November 6, 2017

Review:

• Inference for Proportions

Presentation:

• Virginia Governor’s Race
  • Candidates
    • Ed Gillespie (Republican)
    • Ralph Northam (Democrat)
    • Cliff Hyra (Libertarian)
  • Significance
• Understand relationship with techniques from
  • Sampling Distributions
  • Inference for Proportions
  • Sampling and Surveys

Assignment:

• Read today’s Analysis from Real Clear Politics
• Study the 2013 Virginia Gubernatorial election. Which polls did best 4 years ago?
• Select ten (10) polls from the list at Real Clear Politics
  • Choose polls you believe will provide the most accurate data
• For each of your selected polls, find the following:
  • What is the reported % vote estimate for each of the two major party candidates?
  • What is the reported margin of error?
  • What is the reported sample size?
• Produce your own 95% confidence interval to estimate vote % for both major candidates.
  • Extract data necessary to produce your own calculations
    • you’ll need to calculate p-hat and s (standard deviation)
    • hint:
      • if n = sum of sample sizes, then s = √(p*(1-p)/n)
      • if n = 10, then s = √(ε(x-x-bar)^2/n-1)
  • Clarify how you’re using the polling data
  • Note any assumptions you have to make to facilitate calculations
  • Round point estimates and margins of error to the nearest 3 digits (e.g., 0.466 ± 0.034)
• Write 4 brief paragraphs discussing your analysis and predicting the election outcome
  1. How did you select your sample polls? What was your criteria?
  2. Describe your calculations – how did you use the polling data to generate your estimate?
  3. What is your predicted outcome for the election? Who do you think will win and why?
  4. How does your opinion differ from today’s Analysis from Real Clear Politics?