Predictive Analytics

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12.2 Viewing Observation Distance Matrix

Figure 12.6:

View of the Distance Matrix with table of statistics

There are many ways of ﬁnding relevant subsets of the data presented in an Observation Distance Matrix. You can zoom into a selected area of the graph. You can open a zoomed subset in a new spreadsheet or tree and you can narrow the Distance range.

12.2.1 Viewing Spreadsheets or Trees of Subsets

based on the setting in the pull down menu in the lower right corner (Fig. 12.5) you can left-click and drag to create a spreadsheet or a tree of a subset of the data.

By selecting the Left click and drag for spreadsheet and delineating a rectangle in the upper right of the matrix (Fig. 12.6, the spreadsheet in Figure 12.7 is produced.

Figure 12.7:

Spreadsheet deﬁned in the diagonal area in previous ﬁgure

By selecting the Left click and drag for tree and delineating a rectangle in the upper right of the plot (Fig. 12.6), the tree in Figure 12.8 is produced.

You can do further recursive analysis on this node.

Figure 12.8:

Tree view of the area delineated by the left click and drag

12.2.2 Zooming-In on a Subset of the Distance Matrix Plot

Figure 12.9:

Distance Matrix with horizontal rectangle delineating area to be zoomed-in

If you drag a rectangle with the right button of the mouse and release, the graph is redrawn zooming-in on just that subset of data. In Fig. 12.9 shows the area selected just the center of the matrix plot.

Figure 12.10:

The Matrix plot showing the result of the recalculation of the zoom-in of the prior plot

If it turns out you do not need the data on the current zoom (tab), you can use the “X” on the lower-right corner of the viewer to delete the zoom, both from the view and from the project itself. (If you do not save the project changes, the action of such a deletion will not be saved and the zoom will be retained.)

12.2.3 Narrowing the Distance Range

Figure 12.11:

The two vertical lines on the top Distance color range show the area to be narrowed

Both axes of the Distance Matrix plot have a color coded range. If you wish to delineate a subset of the range, you can click and drag from a point on the low end of the range to a point on the high end. In Fig. 12.11 the vertical lines show an area from about 0.20 to about 0.79 to be narrowed down.

Figure 12.12:

This is the plot redrawn to the narrowed range.

Either axis can be changed to a value other than Distance. In Fig. 12.13 the value is set to the dependent value BP. Once the response is plotted, you can look for regions where the average response is colored in the range you are looking for. For instance, the upper right blue triangle all has blue stripes going down from it, indicating these patients have lower blood pressure. Some of the other clusters have more red stripes, indicating a higher blood pressure for that cluster.

Figure 12.13:

Drop down menu showing lower axis changing from Distance to a response variable BP

12.2.4 Menus

There are also some menus that allow you to save or print the results.

Here is what the menus do:

Menu Steps	Does This
File->Create Bitmap	Allow you to save an image of the Observation Distance Matrix as a BMP ﬁle with out all the controls on the dialog.
File->Print Image	Lets you print the entire dialog with out the clutter of the buttons and controls..
File->Close	Closes the Matrix dialog.
Save Obs. Distance. . .	Saves a comma delimited ﬁle (CSV) for use in other programs.
Close	Closes the dialog.

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