Comparing models

Choosing the best of multiple competing models can be tricky if these models are built on incomplete data. In this exercise, you will extend the model you have built previously by adding one more explanatory variable: the race of the movie's subject. Then, you will try to compare it to the previous model.

As a reminder, this is how you have fitted the first model:

model_1 <- lm(earnings ~ country + year + sub_type, 
              data = biopics)

Let's see if we can judge whether adding the race variable improves the model!