Stats with geoms

Intermediate Data Visualization with ggplot2

Rick Scavetta

Founder, Scavetta Academy

ggplot2, course 2

Statistics
Coordinates
Facets
Data Visualization Best Practices

Statistics layer

Two categories of functions
- Called from within a geom
- Called independently
stats_

geom_ <-> stat_

p <- ggplot(iris, aes(x = Sepal.Width))
p + geom_histogram()

geomhistogram

geom_ <-> stat_

p <- ggplot(iris, aes(x = Sepal.Width))
p + geom_histogram()
p + geom_bar()

geomhistogram

geom_ <-> stat_

p <- ggplot(mtcars, aes(x = factor(cyl),  fill = factor(am))) 
p + geom_bar()
p + stat_count()

The geom_/stat_ connection

`stat_`	`geom_`
`stat_bin()`	`geom_histogram()`, `geom_freqpoly()`
`stat_count()`	`geom_bar()`

stat_smooth()

ggplot(iris, aes(x = Sepal.Length, 
                 y = Sepal.Width, 
                 color = Species)) + 
  geom_point() +
  geom_smooth()

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

stat_smooth(se = FALSE)

ggplot(iris, aes(x = Sepal.Length, 
                 y = Sepal.Width, 
                 color = Species)) + 
  geom_point() +
  geom_smooth(se = FALSE)

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

geom_smooth(span = 0.4)

ggplot(iris, aes(x = Sepal.Length, 
                 y = Sepal.Width, 
                 color = Species)) + 
  geom_point() +
  geom_smooth(se = FALSE, span = 0.4)

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

geom_smooth(method = "lm")

ggplot(iris, aes(x = Sepal.Length, 
                 y = Sepal.Width, 
                 color = Species)) + 
  geom_point() +
  geom_smooth(method = "lm", se = FALSE)

geom_smooth(fullrange = TRUE)

ggplot(iris, aes(x = Sepal.Length, 
                 y = Sepal.Width, 
                 color = Species)) + 
  geom_point() +
  geom_smooth(method = "lm", 
              fullrange = TRUE)

The geom_/stat_ connection

`stat_`	`geom_`
`stat_bin()`	`geom_histogram()`, `geom_freqpoly()`
`stat_count()`	`geom_bar()`
`stat_smooth()`	`geom_smooth()`

Other stat_ functions

`stat_`	`geom_`
`stat_boxplot()`	`geom_boxplot()`

Other stat_ functions

`stat_`	`geom_`
`stat_boxplot()`	`geom_boxplot()`
`stat_bindot()`	`geom_dotplot()`
`stat_bin2d()`	`geom_bin2d()`
`stat_binhex()`	`geom_hex()`

Other stat_ functions

`stat_`	`geom_`
`stat_boxplot()`	`geom_boxplot()`
`stat_bindot()`	`geom_dotplot()`
`stat_bin2d()`	`geom_bin2d()`
`stat_binhex()`	`geom_hex()`
`stat_contour()`	`geom_contour()`
`stat_quantile()`	`geom_quantile()`
`stat_sum()`	`geom_count()`

Let's practice!

Intermediate Data Visualization with ggplot2