Box charts; Is a measure of how data is distributed in a data set. Divides the data set into three to a quarter from the chart. This diagram shows the minimum, maximum, middle, first quadrant, and third quadrant in the data set, as well as a box diagram for each of them; It can be efficient to compare the distribution of data in a data set.

Box diagrams are created using the boxplot () function in R.

Syntax

The basic syntax for creating a box diagram in R is as follows:

boxplot (x, data, notch, varwidth, names, main)

Parameters used in the above coding; as follows:

• x is a vector or a formula.
• data is a data framework.
• notch is a logical value. To draw depressions for each box; Must be set to TRUE.
• varwidth is a logical value. To draw the box width should be adjusted to fit the sample size.
• names A group of names that are printed under each box chart.
• main is used to present a title to the chart.

Example

We used the “mtcars” dataset in the R environment to create a basic box diagram. Let’s take a look at the “mpg” and “cyl” columns in mtcars:

input <- mtcars [, c (‘mpg’, ‘cyl’)]

print (head (input))

When we run the above code; The following result is obtain:

mpg cyl

Mazda RX4 21.0 6

Mazda RX4 Wag 21.0 6

Datsun 710 22.8 4

Hornet 4 Drive 21.4 6

Hornet Sportabout 18.7 8

Valiant 18.1 6

Create box charts

The following script creates a box diagram for the relationship between mpg (miles per gallon) and cyl (number of cylinders).

# Give the chart file a name.

png (file = “boxplot.png”)

# Plot the chart.

boxplot (mpg ~ cyl, data = mtcars, xlab = “Number of Cylinders”,

ylab = “Miles Per Gallon”, main = “Mileage Data”)

# Save the file.

dev.off ()

When we run the above code; The following result is obtain:

Miles per gallon

Number of cylinders

Distance data traveled

Box diagram with recess

We can draw boxes with recesses to see how well the intermediates of different data sets match.

The following script creates a box chart with depressions for each data set.

# Give the chart file a name.

png (file = “boxplot_with_notch.png”)

# Plot the chart.

boxplot (mpg ~ cyl, data = mtcars,

xlab = “Number of Cylinders”,

ylab = “Miles Per Gallon”,

main = “Mileage Data”,

notch = TRUE,

varwidth = TRUE,

col = c (“green”, “yellow”, “purple”),

names = c (“High”, “Medium”, “Low”)

)

# Save the file.

dev.off ()

When we run the above code; We obtain the following Box diagrams result.