To create this plot, we're going to pass in our variables
to ggplot as usual. We'll set x equal to age,
and y equal to median friend count. And we'll set
data equal to the data frame that we just created. So
pf.fc by age, gender. Now I just need to add
gm line and pass up the color parameter inside the unaesthetic
wrapper. This time the color will take on the value
of gender. This will give me one line for males and
one line for females. Running this code, we get the same
exact plot. Hopefully you're feeling like a data guru at this point.