Effective classification of text data based on a word appearance frequency

A classification method comprising:

• acquiring a plurality of text data items each including a question sentence and an answer sentence;
• identifying a first word that exists in each of a plurality of question sentences included in the acquired plurality of text data items, a number of the plurality of question sentences satisfying a predetermined criterion;
• identifying, from the plurality of question sentences, a second word that exists in a question sentence not including the first word and that does not exist in a question sentence including the first word;
• and
• classifying the plurality of text data items into a first group of text data items each including a question sentence in which the identified first word exists and a second group of text data items each including a question sentence in which the identified second word exists.

A classification apparatus comprising:

• a memory;
• and
• a processor coupled to the memory and configured to:
• acquire a plurality of text data items each including a question sentence and an answer sentence,
• identify a first word that exists in each of a plurality of question sentences included in the acquired plurality of text data items, a number of the plurality of question sentences satisfying a predetermined criterion,
• identify, from the plurality of question sentences, a second word that exists in a question sentence not including the first word and that does not exist in a question sentence including the first word, and
• classify the plurality of text data items into a first group of text data items each including a question sentence in which the identified first word exists and a second group of text data items each including a question sentence in which the identified second word exists.