source: orange/docs/widgets/rst/associate/associationrulesexplorer.rst @ 11050:e3c4699ca155

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1.. _Association Rules Explorer:
2
3Association Rules Tree Viewer
4=============================
5
6.. image:: ../icons/AssociationRulesExplorer.png
7
8A tree-like association rules viewer
9
10Signals
11-------
12
13Inputs:
14   - Association Rules
15      A list of rules
16
17
18Outputs:
19   - None
20
21
22Description
23-----------
24
25This widget is a tree-like association rules viewer.
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27The widget can be used to find all the rules that include a particular condition on the left-hand side. The below snapshot is made on the Titanic data set, using the filter as shown on the page on the `Association Rules Filter <AssociationRulesViewer.htm>`_.
28
29.. image:: images/AssociationRulesTreeViewer-closed.png
30   :alt: Association Rules Tree Viewer Widget
31
32Say that we are interested in rules regarding the survival of adults. By opening the branch "age=adult", we discover four rules that contain this condition as the sole condition on the left-hand side, while the right-hand sides contain different combinations of sex, status and survival.
33
34.. image:: images/AssociationRulesTreeViewer-semi-open.png
35   :alt: Association Rules Tree Viewer Widget
36
37Besides that, there are rules with (at least) two conditions on the left-hand side, "age=adult" and "sex=male"; to explore these rules, we would need to open the corresponding branch.
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39Each leaf of the tree corresponds to one particular ordering of the left-hand side conditions in a particular rule. Turned around, this means that each rule appears in many places in the tree. As the completely open tree below shows, the rule :code:`age=adult & sex=male -> status=crew` appears in two places (the seventh and the eleventh row).
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41On the left-hand side of the widget, we can choose the measures we want to observe. Let L, R and B be the number of examples that fit the left, the right and both sides of the rule, respectively, and N the total number of examples in the data set. The measures are then defined as follows
42
43   - confidence = B / L
44   - confidence = B / L
45   - coverage = L / N
46   - strength = R / L
47   - lift = N * B / (L * R)
48   - leverage = N * B - L * R
49
50
51
52:obj:`Tree depth` sets the depth to which the tree is expanded. If, it is set to, for instance, three, then the leaves corresponding to rules with five conditions will, besides the right-hand side, also contain the two conditions which are not shown in the branches.
53
54With :obj:`Display whole rules` we can decide whether we want the entire rule (including the information that is already contained in the branches, that is, in the path from the root to the rule) reprinted again in the leaf.
55
56Examples
57--------
58
59This widget is typically used with the `Association Rules <AssociationRules.htm>`_ and possibly `Association Rules Filter <AssociationRulesViewer.htm>`_. A typical schema is shown below.
60
61.. image:: images/AssociationRules-Schema.png
62   :alt: Association Rules
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