What are missing groups and empty cells?

In the following worksheet, the two grouping variables Style and Size each cycle through three values. However, not all logical combinations are represented:
  • The group Hooded/Large does not appear here. This combination is considered an "empty cell". You might exclude empty cells simply to save space on your graph, or to show that the group does not exist.
  • One row pairs a missing value in the Style column with Small in the Size column. This pairing is considered a "missing group".
C1-T C2-T C3
Style Size Quantity
Short Small 4
Short Medium 6
Short Large 3
Long Small 3
Long Medium 7
Long Large 2
  Small 5
Hooded Small 1
Hooded Medium 4

Include or exclude missing groups and empty cells

  • To control how missing values and empty cells are graphed, in the graph creation dialog box click Data Options and then click the Group Options tab.

Examples of including or excluding missing groups and empty cells

The following examples graph data from the previous worksheet to show all possible combinations.

Do not include missing as a group, do not include empty cells

If you deselect both Include missing as a group and Include empty cells, Minitab excludes the group Hooded/Large and the group created by a missing value and Small.

Include missing as a group, Do not include empty cells

If you select only Include missing as a group, Minitab includes a bar for the "missing group" formed by an empty cell and the value Small.

Do not include missing as a group, include empty cells

If you select Include empty cells, Minitab includes an empty placeholder for the group Hooded/Large.

Include missing as a group, include empty cells

If you check both Include missing as a group and Include empty cells (the defaults), Minitab includes both empty cell and missing groups from the earlier examples, as well as the empty cells created by their combination (a missing value with "Medium" and a missing value with "Large"). When used in the context of paneling, these options have a similar effect on the number of panels created.

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