Distribution of one variable

Exploratory Data Analysis in R

Andrew Bray

Assistant Professor, Reed College

Marginal vs. conditional

ggplot(cars, aes(x = hwy_mpg)) +
  geom_histogram()
`stat_bin()` using `bins = 30`. Pick better value with `binwidth`.
Warning message:
Removed 14 rows containing non-finite values (stat_bin). 

ch2_2.003.png

Exploratory Data Analysis in R

Marginal vs. conditional

ggplot(cars, aes(x = hwy_mpg)) +
  geom_histogram() +
  facet_wrap(~pickup)
`stat_bin()` using `bins = 30`. Pick better value with `binwidth`.
Warning message:
Removed 14 rows containing non-finite values (stat_bin).

ch2_2.006.png

Exploratory Data Analysis in R

Building a data pipeline

cars2 <- cars %>%
  filter(eng_size < 2.0)

ggplot(cars2, aes(x = hwy_mpg)) +
  geom_histogram()
Exploratory Data Analysis in R

Building a data pipeline

cars %>%
  filter(eng_size < 2.0) %>%
  ggplot(aes(x = hwy_mpg)) +
  geom_histogram()
Exploratory Data Analysis in R

Filtered and faceted histogram

cars %>%
  filter(eng_size < 2.0) %>%
  ggplot(aes(x = hwy_mpg)) +
  geom_histogram()
`stat_bin()` using `bins = 30`. Pick better value with `binwidth`.

ch2_2.011.png

Exploratory Data Analysis in R

Wide bin width

cars %>%
  filter(eng_size < 2.0) %>%
  ggplot(aes(x = hwy_mpg)) +
  geom_histogram(binwidth = 5)

ch2_2.013.png

Exploratory Data Analysis in R

Density plot

cars %>%
  filter(eng_size < 2.0) %>%
  ggplot(aes(x = hwy_mpg)) +
  geom_density()

ch2_2.015.png

Exploratory Data Analysis in R

Wide bandwidth

cars %>%   
  filter(eng_size < 2.0) %>%
  ggplot(aes(x = hwy_mpg)) +
  geom_density(bw = 5)

ch2_2.017.png

Exploratory Data Analysis in R

Let's practice!

Exploratory Data Analysis in R

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