title: Classifying unlabelled data in Weka
body: <p>I'm currently using various classifiers in Weka.</p>
  
  <p>My testing data is labelled, e.g.:</p>
  
  <pre><code>@relation bmwreponses
  
  @attribute IncomeBracket {0,1,2,3,4,5,6,7}
  @attribute FirstPurchase numeric
  @attribute LastPurchase numeric
  @attribute responded {1,0}
  
  @data
  4,200210,200601,0
  5,200301,200601,1
  6,200411,200601,0
  5,199609,200603,0
  6,200310,200512,1
  ...
  </code></pre>
  
  <p>The last value per row is the class element, i.e. responded.</p>
  
  <p>But if I try unlabelled test data, e.g.:</p>
  
  <pre><code>@relation bmwreponses
  
  @attribute IncomeBracket {0,1,2,3,4,5,6,7}
  @attribute FirstPurchase numeric
  @attribute LastPurchase numeric
  @attribute responded {1,0}
  
  @data
  4,200210,200601,?
  5,200301,200601,1
  6,200411,200601,?
  5,199609,200603,0
  6,200310,200512,?
  ...
  </code></pre>
  
  <p>Weka will carry out the classification but ignore the unlabelled rows. So the test above will only include rows 1 and 3.</p>
  
  <p>Does anyone know how to get around this? Should I have the class attribute declared in the test file or am I missing something?</p>
  
  <p>Mr Morgan.</p>