Exercise

Modifying stat_smooth (2)

In this exercise we'll take a look at the standard error ribbons, which show the 95% confidence interval of smoothing models. ggplot2 and the Vocab data frame are already loaded for you.

Vocab has been given an extra column, year_group, splitting the dates into before and after 1995.

Instructions 1/2

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1
- Using Vocab, plot vocabulary vs. education, colored by year_group.
- Use geom_jitter() to add jittered points with transparency 0.25.
- Add a smooth linear regression stat (with the standard error ribbon).
2
It's easier to read the plot if the standard error ribbons match the lines, and the lines have more emphasis.
- Update the smooth stat.
  
  Map the fill color to year_group.
  
  Set the line size to 2.