A criterion for attributes in rough set theory and its application to analysis on the relation between human psychological mood state and the immune function

Recent behavioural medicine studies have revealed that the human secretory substances change according to his/her mental states. Especially, those substances transiently get increase (or decrease) against the short-term experimental stressors. However, the relation with rather longer stressor, or daily stressor, has not yet well understood or reported discrepant results. One possible reason for this discrepancy might be brought from uncertainty of the psychological evaluation, which is the score of subjective questionnaire. We then introduced an evaluation criterion of attributes based on rough set theory to analyze the relation between the psychological state and a major immune substance. As a result, several items in the questionnaire were extracted as dominant items, while there was still no correlation between them.