How to create a box (and whisker) plot (in R)
Task
A box plot, or a box and whisker plot, shows the quartiles of a single variable from a dataset (one of which is the median) and may also show the outliers. It is a simplified way to see the distribution of a variable. Sometimes multiple box plots (one for each of several variables) are shown side-by-side on a plot, to compare the variables. How can we create such graphs?
Related tasks:
- How to create basic plots
- How to add details to a plot
- How to create a histogram
- How to change axes, ticks, and scale in a plot
- How to create bivariate plots to compare groups
- How to plot interaction effects of treatments
Solution
We will create some fake data using vectors, for simplicity. But everything we show below works also if your data is in columns of a DataFrame.
1
2
3
patient_id <- c(0, 1, 2, 3, 4, 5, 6, 7, 8, 9)
patient_height <- c(60, 64, 64, 65, 66, 66, 70, 72, 72, 76)
patient_weight <- c(141, 182, 169, 204, 138, 198, 180, 175, 244, 196)
We can use R’s boxplot() function to make the plot.
1
boxplot(patient_weight)
You can show more than one variable’s box plot side-by-side by passing both variables into the boxplot() function.
1
boxplot(patient_height, patient_weight)
Content last modified on 24 July 2023.
See a problem? Tell us or edit the source.
Contributed by Elizabeth Czarniak (CZARNIA_ELIZ@bentley.edu)