Chapter 10 Box plot
Boxplots are normally used to inspect the distribution of continuous (cardinal, e.g. interval or ratio-level) variables.
10.1.1 Example dataset
From this dataset, this example uses variable
10.2 Input: jamovi
Open the “Exploration” menu and select the “Descriptives” option as shown in Figure 10.1.
In the “Descriptives” dialog that appears, expand the “Plots” section at the bottom and check the checkbox labelled “Box plot” as shown in Figure 10.2.
Select the variable(s) for which you want to produce a box plot by dragging those variables from the list at the top left to the box marked “Variables” just to the right of that list. The box plot will be automatically produced in the output pane on the right-hand side.
10.3 Input: R
10.3.1 R: rosetta
10.3.2 R: base
This requires the example dataset to be stored under name
dat, see section 3.
10.4 Input: SPSS
10.4.1 SPSS: GUI
First activate the
dat dataset by clicking on it (see 2.4.1).
Open the “Graphs” menu and select the “Chart Builder” option as shown in Figure 10.3.
In the “Chart Builder” dialog, select “Boxplot” from “Gallery” and drag “1-D Boxplot” to the “Chart Preview” as shown in Figure 10.4.
Under the “Variables” menu, select “xtcUsePillHigh” and drag it onto the “X-Axis?” option in “Chart Preview” as shown in Figure 10.5. The variable you put on the vertical x-axis must be labeled as “scale” type. Note that there are options to modify the aesthetics of the graph on the right side of the screen under “Element Properties”, “Chart Appearance”, and “Options”.
Press OK and the graph will appear in the SPSS output window.
10.4.2 SPSS: Syntax
Use the following command (this requires the
dat dataset to be the active dataset, see 2.4.1):
GRAPH /BOXPLOT = xtcUsePillHigh.