Exercise 8. Comparing to actual results by pollster

Although the proportion of confidence intervals that include the actual difference between the proportion of voters increases substantially, it is still lower that 0.95. In the next chapter, we learn the reason for this.

To motivate our next exercises, calculate the difference between each poll's estimate \(\bar{d}\) and the actual \(d=0.021\). Stratify this difference, or error, by pollster in a plot.

Define a new variable errors that contains the difference between the estimated difference between the proportion of voters and the actual difference on election day, 0.021.
To create the plot of errors by pollster, add a layer with the function geom_point. The aesthetic mappings require a definition of the x-axis and y-axis variables. So the code looks like the example below, but you fill in the variables for x and y.
The last line of the example code adjusts the x-axis labels so that they are easier to read.

data %>% ggplot(aes(x = , y = )) +
  geom_point() +
  theme(axis.text.x = element_text(angle = 90, hjust = 1))

Parameters and Estimates

Introduction to Inference

Confidence Intervals and p-Values

Statistical Models

Bayesian Statistics

Election Forecasting

The t-distribution

Association and Chi-Squared Tests

Exercise

Exercise 8. Comparing to actual results by pollster

Instructions