I am trying to classify a question type, as a "Type" . It can be classified into 6 types. I am using an ARFF file as input to weka with 99 training entries. I have got a model in place, and it has an accuracy of 85% (obtained using cross validation), which is to my satisfaction.

Now, when I want to test this, using a new data set, I am getting :

=== Summary ===

Total Number of Instances 0
Ignored Class Unknown Instances 7

There were 7 rows in my data. All of them seem to have been ignored.

I am new to weka and cross validated, can someone please tell me what must be going wrong here?

Here is my test input file:

@relation TypeModel

@attribute Type {person,date,object,number,place,boolean} @attribute who {no,yes} @attribute what {no,yes} @attribute when {no,yes} @attribute where {no} @attribute which {no,yes} @attribute how {no,yes} @attribute city {no,yes} @attribute state {no,yes} @attribute country {no,yes} @attribute '?' {no,yes} @attribute day {no,yes} @attribute is {no,yes} @attribute people {no,yes} @attribute person {no} @attribute president {no,yes} @attribute 'how many' {no,yes} @attribute 'give me all' {yes,no}

@data ?,no,no,no,no,no,no,no,no,no,no,no,no,no,no,no,no,yes ?,no,no,no,no,no,yes,no,no,no,no,yes,no,no,no,no,no,no ?,yes,no,no,no,no,no,no,no,no,yes,no,no,no,no,no,no,no ?,no,no,no,no,yes,no,no,no,no,yes,no,no,no,no,no,no,no ?,no,no,no,no,no,yes,no,no,yes,yes,no,no,no,no,no,yes,no ?,no,no,no,no,yes,no,yes,no,no,yes,no,no,no,no,no,no,no ?,no,no,no,no,no,no,no,no,no,yes,no,yes,no,no,yes,no,no


Type is the first element in your arff file for each row. You want to classify according to that but they all have '?', unknown values. Since weka don't know what they are, it can't give you a result of classification.


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