ABSTRACT
In this paper we discuss different interpretations of the concept of probability. The subjective interpretation makes it possible to do statistical inference by Bayes theorem, and thereby it is most useful for the upgrading of the decision maker's knowledge. We briefly comment the treatment and interpretation of the parametric uncertainty in the context of probabilistic safety assessment (PSA). The concepts of 'expected utility' and 'value of information', which are of central importance in the decision theory, are also presented.
