Presents a model of tests and measurement that identifies test scores with Hilbert space vectors and true and error components of scores with linear operators. This geometric point of view brings to light relations among elementary concepts in test theory, including reliability, validity, and parallel tests. (Author/SLD)

This seventh in a series of articles discussing expert system construction focuses on two ways to create a structure that determines a decision: (1) rule-based, or deductive, implementation; and (2) example-based, or inductive, implementation. Probability factors and confidence levels are discussed, and an example is given for selecting an…

Discusses the probabilities and positive and negative predictive values of medical tests for HIV. (MKR)

Discussion of authorship distributions focuses on the results of a numerical study for fractional authorship attribution. Highlights include coauthors; multinomial coefficients; Lotka functions; probability distributions of articles per author; and probability distributions of authors per article. (LRW)

The phenomenon of 2 x 2 x 2 arrays having nonmaximal rank with positive probability, pointed out by J. Kruskal (1989), is generalized to 2 x "n" x "n" arrays. It is concluded that a pair of asymmetric square matrices can be diagonalized simultaneously with positive probability. (SLD)

Discussion of probabilistic information retrieval (IR) systems challenges the probability ranking principle in IR from the perspective of (1) signal detection-decision theory and (2) utility theory. Calibration, certainty, and independent assessment are discussed in terms of the relevance of documents, and standard retrieval policies are analyzed.…

The phimax adjustment to phi (Pearson's product moment correlation applied to binary data) is explored. Phi/phimax is shown to be a measure of relationship apart from its affiliation with phi. The relations between phi/phimax and kappa and limitations of phi/phimax are discussed. (SLD)

A model for preferential and triadic choice is derived in terms of weighted sums of central F distribution functions. It is a probabilistic generalization of Coombs' (1964) unfolding model from which special cases can be derived easily. This model for binary choice can be easily related to preference ratio judgments. (SLD)

Reports on conditions under which people's probability judgments are superadditive rather than subadditive. Both directions of deviation from additivity are interpreted in a common framework, in which probability judgments are often mediated by judgments of evidence. The two kinds of nonadditivity result from differences in recruitment of…

Six- to 14-year olds added "winning" beads to an urn of "losing" beads in order to generate equal probabilities of choosing a winning bead from each of two urns. Found that 13-year olds integrated the two dimensions (winning and losing beads), the youngest children relied on one dimension, and 9- to 10-year olds partly combined…

Describes similarities and differences between additive conjoint measurement and the Rasch model, and formalizes some new nonparametric item response models that are, in a sense, probabilistic measurement theory models. Applies these new models to published and simulated data. (SLD)

Reports on a study designed to provide baseline data in the area of conjunction and conditional events. Cross-sectional and longitudinal analyses revealed improvement with grade in expressing probability numerically and distinguishing conditional events, but no change in incidence of conjunction errors. (Author/MM)

Compares four methods that map outlier statistics to a familiarity probability scale (a "P" value). Explored these methods in the context of computerized adaptive test data from a 1995 nationally administered computerized examination for professionals in the medical industry. (SLD)

The purpose of this note is to give a construction method for measures of central tendency and dispersion of a set of data on the basis of some symmetric multivariate functions and distance functions. Several examples regarding the known and new measures are presented. (Author/MM)

Statistics are offered to "prove" odds against the origin of life. Presents a summary analysis of all known examples to be used to check these claims whenever they are brought up in conversations, debates, books, or articles. Addresses scientific work misused by anti-evolutionists and the pseudoscientific assertions of the…