Abstract
In this paper, we propose a method of the list-type question-answering. The list-type question-answering is the task in which a system is requested to enumerate all correct answers to given question. In the method, we utilize the distribution of the score that an existing question answering system gives to answer candidates. Answer candidates are separated into some clusters according to their scores. Here, we assume that each cluster results from a probabilistic model. Under the assumption, the parameters of these probabilistic distribution models are estimated by using the EM algorithm. Then, the method judges whether each distribution model is a source of correct answers or a source of incorrect answers. Answer candidates that originate from the distribution models corresponding to correct answers are regarded as final answers. Moreover, by comparing model parameters, we can also judge whether or not the question-answering system appropriately found correct answers. The experimental results show that the use of the score distribution is effective in the list-type question-answering.
