Building a Statistical Expert System with Knowledge Bases of Different Levels of Abstraction

Statistical analysis is predetermined by the way a (prospective) experiment is planned or data are collected in a (retrospective) study. The a-priori knowledge of observable, theoretical and hypothetical relations (WITTKOWSKI 1987) determines the semantically meaningful database activities and statistical analyses. For instance, relations between variables and types of observational units may be used to determine whether or not the meaning of a value depends on values of other variables. The models underlying the statistical methods are determined by theoretical knowledge on the sampling strategy of factors, scales, and constraints (WITTKOWSKI 1985). For confirmatory analyses, the primary goal (hypothesis) needs to be specified at the time the sample size is computed.