Box Plot with ANOVA
A box plot with ANOVA analysis displays a box and whisker plot with corresponding analysis of variance in the sample(s).
To begin the analysis, see Running the Analyses, then perform the following steps.
To perform a box plot with ANOVA analysis:
Click the Advanced Workflow tab, then open the Analysis menu.
Select Box Plot with ANOVA.
The Variable Selection section appears.
Define an independent variable and a dependent variable, following the instructions above the boxes. You must use one categorical variable and one continuous variable. The boxes are plotted based on the categorical variable:
- If the independent variable is categorical, the boxes are plotted horizontally.
- If the dependent variable is categorical, the boxes are plotted vertically.
- If you select two continuous variables, you must bin one to create a categorical value.
Optionally, enable binning by selecting Enable binning.
Data binning refers to a pre-processing technique used to reduce minor observation errors. Clusters of data are replaced by a value representative of that cluster (the central value). For information on binning, see Data Binning Using Box Plot with ANOVA.
Your analysis appears below:
Data Binning Using Box Plot with ANOVA
When conducting a Box Plot with ANOVA analysis, at least one of the variables selected should be a continuous variable (for example, age), and the other should be a categorical value (for example, tumor stage).
A continuous variable can be viewed as a categorical value using the binning feature, described below. Alternatively, binning can be used to regroup categorical data to consider it as a single variable. For example, if histological grade with values such as Well Defined, Moderately Well Defined, and Poorly Defined are selected, you can group Moderately Well Defined with Poorly Defined and treat them as one group for the purposes of this analysis.
To use the data binning feature with a box plot analysis:
Begin to set up a Box Plot with ANOVA analysis by following the instructions in section Box Plot with ANOVA.
Enable binning by selecting Enable binning.
Define the following and then click Run.
Select which variable should define the groups (Independent or Dependent) from the dropdown menu.
If the independent variable defines the groups, boxes will be plotted horizontally. If the dependent variable defines the groups, boxes will be plotted vertically
- Variable Type
Select whether the variable you have defined above is continuous or categorical from the dropdown menu.
A continuous variable can be turned into a categorical variable when you use the binning feature.
- Number of Bins
Type the number of bins you would like data to be organized in.
This step may require trial and error based on how you want to display data.
- Bin Assignments
Select how you would like data to be binned from the dropdown menu.
This feature can only be used when the variable type selected above is continuous.
What to use when:
Evenly Distribute Population: Assigns bins based on the underlying data.
For example, if the majority of the subjects in the study were elderly, bins based on age could look like: [(1-40), (40-80), (81-85), (86-90), (90-92)].
Evenly Spaced Bins: Creates bins based on the overall range of the variable.
For example, if the majority of the subjects in the study were elderly, bins based on age could look like: [(1-20), (21-40), (41-60), (61-80), (81-100)].
- Manual Binning
Select the checkbox if you want to bin manually.
This is the only binning method available if you are trying to bin a categorical variable type.
Complete the binning form that populates as a result of checking the Manual Binning box.
For continuous data:
For categorical data: