This exercise will use the data you found for Exercise 4.7. This time, rather than repeating the same analysis across each year, or country (or whatever group the data varies across), fit a multilevel...

This exercise will use the data you found for Exercise 4.7. This time, rather than repeating the same analysis across each year, or country (or whatever group the data varies across), fit a multilevel model using lmer() instead. Compare the results to those obtained in your earlier analysis.