Box Plots

[#1]

Use to display the distribution of continuous variables. Boxplots are based upon a set of summary statistics that describe the center and spread of data. Boxplots are a very useful way for comparing data bewteen groups.

Box Plots – One Variable

1. From an open JMP^® data table, select Analyze > Distribution.
2. Click on one or more continuous variables from Select Columns, and Click Y, Columns (continuous variables have blue triangles). Click OK.

• An outlier box plot is displayed by default next to the histogram (or above if horizontal layout is used).
• To display a quantile box plot, select the option from the red triangle for the variable.

The Outlier Box Plot shows the box, plus:
• IQR = the 3rd quartile minus the 1st quartile.
• Whiskers drawn to the furthest point within 1.5 x IQR from the box.
• Potential outliers (disconnected points).
• A red bracket defining the shortest half of the data (the densest region).
• A confidence diamond showing the mean (middle of the diamond) and the upper and lower bound of a 95% confidence interval for the population mean.

Box Plots – Two Variables

1. Select Analyze > Fit Y by X.
2. Click on a continuous variable from Select Columns, and Click Y, Response.
3. Click on a categorical variable and click X, Factor (categorical variables have red or green bars). Click OK.
   • The Oneway Analysis output window will display.
4. Click on the red triangle, and select Display Options > Box Plots to display quantile box plots, or select Quantiles to display both box plots and a numeric table with the quantile values. 

Notes: Box plots for one or more variables can also be generated from Graph > Graph Builder.

Companies.jmp (Help > Sample Data Folder)

Visit Discovery JMP > Visualize Your Data, Basic Analysis > Distributions > Options for Continuous Variables, and Basic Analysis > Oneway Analysis in JMP Help to learn more.