Understanding variables

In the previous exercise you saw that disp can be mapped onto a color gradient or onto a continuous size scale.

Another argument of aes() is the shape of the points. There are a finite number of shapes which ggplot() can automatically assign to the points. However, if you try this command in the console:

ggplot(mtcars, aes(wt, mpg, shape = disp)) +
  geom_point()

It gives an error. What does this mean?

Possible answers

shape is not a defined argument.

shape only makes sense with categorical data, and disp is continuous.

shape only makes sense with continuous data, and disp is categorical.

shape is not a variable in your dataset.

shape has to be defined as a function.

Exercise

Understanding variables

Instructions

Possible answers