source: orange/docs/widgets/rst/classify/majority.rst @ 11050:e3c4699ca155

Revision 11050:e3c4699ca155, 1.7 KB checked in by Miha Stajdohar <miha.stajdohar@…>, 16 months ago (diff)

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1.. _Majority:
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3Majority Learner
4================
5
6.. image:: ../icons/majority.png
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8A Learner that returns the majority class, disregarding the example's attributes
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10Signals
11-------
12
13Inputs:
14
15
16   - Examples (ExampleTable)
17      A table with training examples
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19
20Outputs:
21
22   - Learner
23      The "learning" algorithm.
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25   - Classifier
26      The classifier
27
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29Signal :code:`Classifier` sends data only if the learning data (signal :code:`Examples`) is present.
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31Description
32-----------
33
34This widget provides a graphical interface to a learner which produces a classifier that always predicts the majority class. When asked for probabilities, it will return the relative frequencies of the classes in the training set. When there are two or more majority classes, the classifier chooses the predicted class randomly, but always returns the same class for a particular example.
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36The widget is typically used to compare other learning algorithms with the default classification accuracy.
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38As all other widgets for classification, this one provides a learner and classifier, the former can be fed into widgets for testing learners, while the classifier itself is, well, not very useful.
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40
41.. image:: images/Majority.png
42   :alt: Majority
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44The only option is the name under which it will appear in, say, :code:`Test Learners`. The default name is "Majority". When you change it, you need to click :obj:`Apply`.
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46Examples
47--------
48
49In a typical use of this widget, it would be connected to `Test Learners <../Evaluate/TestLearners.htm>`_ to compare the scores of other learning algorithms (such as kNN, in this schema) with the default scores.
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51.. image:: images/Majority-Knn-SchemaLearner.png
52   :alt: A Schema with Majority Classifier
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