Frequency Plots

Author

Schwab

Libraries

library(tidyverse)

Recall Variable Types

Categorical Variables in R are called:

  • Character variables

  • Factors

Numeric Variables in R are called:

  • Integer

  • Double

Create Histograms

To see the spread, center and shape of a numeric variable.

starwars |>
  ggplot(aes(x= height )) +
  geom_histogram()

Histograms

  1. Make bins for the numbers
  2. Counts the occurrence of a value within bins
  3. The height is the number of counts.

We can adjust the bin or bin size.

Create Bar graph

Visualize the counts of a categorical variable

starwars |>
  ggplot(aes(x = hair_color))+
  geom_bar()

Two bar graphs

Use geom_bar() is data is not precounted

Use geom_col() if data is precounted.

starwars |>
  count(hair_color, name = "no_of_characters") |>
  ggplot(aes(x= hair_color, y= no_of_characters)) +
  geom_col()

Create Facets

We can split graphs by another categorical or discrete variable.

starwars |>
  ggplot(aes(x = hair_color))+
  geom_bar() +
  facet_wrap(~gender)+
  theme(axis.text.x = element_text(angle = 90)) # rotating text so its easier to read

Too many facets

Be careful too many facets can obscure the visualization.

starwars |>
  ggplot(aes(x = hair_color))+
  geom_bar() +
  facet_wrap(~species) +
  theme(axis.text.x = element_text(angle = 90))

Try one

Facet starwar’s characters’ height by their gender.