The study investigates the purposes, functions and requirements of statistical expert systems and focuses attention on some unique characteristics of this subcategory of knowledge-based systems. Statistical expert systems have been considered in this thesis as one approach to improve statistical software and extend their safe usability to a broad category of users in different phases of a statistical investigation. Some prototype applications in which the author has been involved are presented and discussed. A special chapter is devoted to the question whether this methodology might be a rare example of an advanced technology that is suitable for application in non-advanced environments, such as in developing countries.