Single Set of Data
Enter the data in one column. To make a boxplot of the data, go to the Graphs pull down menu and go down to boxplot.
The following window will appear.

Select C1 by double clicking on it. Hit o.k. This will make a boxplot of single set of data.

Multiple Sets of Data in the Same Column

The data should look like the following.

Length     Type
34             1
33             1
35             1
34             1
35             1
33             2
32             2
34             2
23             2
32             2
34             2

Go to Graph, Boxplot. You should get the following window.

Enter the quantitiative variable in Y and the type in X.

You should get a graph that looks like the above image.

Multiple Sets of Data for Data in Seperate Columns
Your data should look like this.

Type 1: Type 2: Type 3:
350        350         350
350        354         361
350        359         362
358        363         364
370        365         364
370        368         365
370        369         366
371        371         371
371        373         377
372        374         377
372        376         377
384        380         379
391        383         380
391        388         380
392        392         392
 

Go to Graphs, Boxplots. Your screen should look like the following.

Enter the three sets of data as three seperate y observations. Now, click on Frames, Multiple Graphs. The following window will appear.

Chose "Overlay graphs on the same page".

You will get the following boxplots in the above image.