Empirical Cumulative Distribution Function

eCDF

The Empirical Cumulative Distribution Function is used to examine a distribution.

A Single Group

Below is the code used to create an ecdf using the mpg variable from the the mtcars dataset.

library(dplyr)
library(ggplot2)

mtcars %>% 
  ggplot(aes(x = mpg)) + 
    stat_ecdf(geom = "point")

The step option in the stat_ecdf() function adds lines to the points.

mtcars %>% 
  ggplot(aes(x = mpg)) + 
    stat_ecdf(geom = "step")

Multiple Groups

Below is the code used to create an ecdf using the mpg separated by transmission type, am. This will generate an ecdf for each m group

library(dplyr)
library(ggplot2)

mtcars <- mtcars %>% mutate( am = factor(am, labels=c("Automatic", "Manual")))

mtcars %>% 
  ggplot(aes(x = mpg, group = am, shape = am)) + 
    stat_ecdf(geom = "point") + 
    scale_shape_discrete(name  ="Transmission")

Mathematicss, Computer Science, and Statistics Department Gustavus Adolphus College