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Thissen, David; Wainer, Howard – 1983
A statistical method is described and illustrated which provides confidence envelopes around item response functions. Examples of 95 percent confidence envelopes for the one-, two-, and three-parameter logistic response models are given. In addition, the authors describe N-line plots, which show the genesis of the envelope as well as the density…
Descriptors: Graphs, Latent Trait Theory, Mathematical Formulas, Mathematical Models
Peer reviewed Peer reviewed
Rousseau, Ronald – Journal of Documentation, 1987
Proposes a new definition of the nuclear zone of a Bradford or Leimkuhler curve. The mathematical rationale is outlined, and examples of the application of this technique to citation analysis are given. (15 references) (CLB)
Descriptors: Citation Analysis, Functions (Mathematics), Graphs, Logarithms
Peer reviewed Peer reviewed
Mazur, Zygmunt – Information Processing and Management, 1984
Investigates the properties of a global model consisting of "n" local information retrieval systems based on thesaurus. Definitions of a distributed information retrieval system (thesaurus, documents set, set of queries) and proofs of theorems denoting further properties of the systems are highlighted. Five references are included. (EJS)
Descriptors: Information Retrieval, Information Systems, Mathematical Formulas, Mathematical Models
Peer reviewed Peer reviewed
Burrell, Quentin L. – Journal of Documentation, 1986
Correlation structure of the Burrell and Cane mixed Poisson model for library loans with aging is presented and illustrated by data from University of Sussex. The approach is compared and contrasted with that originally formulated by Morse and recently reevaluated by Beheshti and Tague. Directions for future investigations are suggested. (Author)
Descriptors: Correlation, Library Circulation, Library Materials, Literature Reviews
Peer reviewed Peer reviewed
Fox, R. O.; Fan, L. T. – Chemical Engineering Education, 1990
Discusses the master equation of a stochastic model in chemical process systems. Presents a solution technique known as the System Size Expansion. (YP)
Descriptors: Chemical Engineering, Chemical Reactions, Engineering, Equations (Mathematics)
Peer reviewed Peer reviewed
Stacey, Kaye – Educational Studies in Mathematics, 1989
Explored are responses of students aged 9 to 13 to linear generalizing problems from both a technical and strategic point of view. The methods commonly used were the same in all age groups and across all three questions, although some students choosing each model varied. (YP)
Descriptors: Elementary Education, Elementary School Mathematics, Junior High Schools, Mathematical Applications
Hart, Roland J.; Bradshaw, Stephen C. – 1981
This report provides the statistical tools necessary to measure the extent of error that exists in organizational record data and group survey data. It is felt that traditional methods of measuring error are inappropriate or incomplete when applied to organizational groups, especially in studies of organizational change when the same variables are…
Descriptors: Adults, Analysis of Variance, Error of Measurement, Mathematical Formulas