9.11

#par(mar = c(4, 4, .1, .1))

ggplot(mpg, aes(x = displ, y = hwy)) +
  geom_smooth()

## `geom_smooth()` using method = 'loess' and formula = 'y ~ x'

ggplot(mpg, aes(x = displ, y = hwy)) +
  geom_smooth(aes(group = drv))

## `geom_smooth()` using method = 'loess' and formula = 'y ~ x'

ggplot(mpg, aes(x = displ, y = hwy)) +
  geom_smooth(aes(color = drv), show.legend = FALSE)+geom_smooth()

## `geom_smooth()` using method = 'loess' and formula = 'y ~ x'
## `geom_smooth()` using method = 'loess' and formula = 'y ~ x'