The frequently neglected and often misunderstood relationship between classical test theory and item response theory is discussed for the unidimensional case with binary measures and no guessing. It is pointed out that popular item response models can be directly obtained from classical test theory-based models by accounting for the discrete…

Being able to characterize the size of raindrops is useful in a number of fields including meteorology, hydrology, agriculture and telecommunications. Associated with this article are data sets containing surface (i.e. ground-level) measurements of raindrop size from two different instruments and two different geographical locations. Students may…

Constructing formulas "from scratch" for calculating geometric measurements of shapes--for example, the area of a triangle--involves reasoning deductively and drawing connections between different methods (Usnick, Lamphere, and Bright 1992). Visual and manipulative models also play a role in helping students understand the underlying…

Proposes that document space and query space have different structures in information retrieval and discusses similarity measures, term independence, and linear structure. Examples are given using the retrieval functions of dot-product, the cosine measure, the coefficient of Jaccard, and the overlap function. (Contains 28 references.) (LRW)

Presents a visualization tool for information retrieval that can display two different similarity measures, angle and distance, in the same space. Discusses the visual display of information-retrieval evaluation models and develops a new retrieval means based on the visual retrieval tool, the controlling bar. (Author/LRW)

Introduces a new generalization of inner product measures which removes the aesthetic deficiencies in previous research. Discusses linear similarity measures; proves the existence theorem for acceptable ranking functions in the case of a linear measure; and defines asymptotic inner product measures. (AEF)

Discussion of information retrieval and relevance focuses on mutual information, a measure which represents the relation between two words. A model of a natural-language information-retrieval system that is based on a two-level document-ranking method using mutual information is presented, and a Korean encyclopedia test collection is explained.…

Describes an evaluation model for expansion systems in information retrieval, i.e., systems expanding a user selection of documents to provide the user with a larger set of documents sharing the same or related characteristics. Highlights include a test protocol and evaluation measures for the efficiency of expansion systems. (Contains 29…

Looking back on enrollment trends in higher education in Britain since 1800, this study examines the trend toward expansion and the philosophy behind such expansion. A statistical model is developed for enrollment trends, and recent literature on enrollment is examined in light of the model presented. (MSE)

Sprinting is described by a simple physical model. The model is used to predict the differences between the recorded times for races on a straight track and on a curve. It is shown that the choice of the running lane makes a nonnegligible difference. (Author/SK)

Research in goal theory has often relied on the general linear model, ignoring some central assumptions of the theoretical framework under investigation. The purpose of the two studies reported here was to illustrate how the Rasch model can supplement traditional statistical analyses when evaluating the effects of goal orientations on persistence.…

The flexibility of an educational program, institution, or system can be described as the ability of the unit to absorb negative responses, such as reductions in funding or enrollments, and continue to function in a viable manner. One approach to adjustment to such reductions is to effect cuts in personnel, current, and equipment spending. This…