Viewing box plots

An example of a box plot of a two-group experiment with 12 samples is shown in figure 31.26.

Image box_plot_two-group
Figure 31.26: A box plot of 12 samples in a two-group experiment, colored by group.

Note that the boxes are colored according to their group relationship. At the bottom you find the names of the samples, and the y-axis shows the expression values. The box also includes the IQR values (from the lower to the upper quartile) and the median is displayed as a line in the box. The ends of the boxplot whiskers are the lowest data point within 1.5 times the inter quartile range (IQR) of the lower quartile and the highest data point within 1.5 IQR of the upper quartile.

It is possible to change the default value of 1.5 using the side panel option "Whiskers range factor".

In the Side Panel to the left, there is a number of options to adjust this view. Under Graph preferences, you can adjust the general properties of the box plot (see figure 31.27).

Image box_plot_graph_preferences
Figure 31.27: Graph preferences for a box plot.

Below the general preferences, you find the Lines and dots preferences, where you can adjust coloring and appearance (see figure 31.28).

Image box_plot_dot_preferences
Figure 31.28: Lines and dot preferences for a box plot.

Note that if you wish to use the same settings next time you open a box plot, you need to save the settings of the Side Panel.