In the subject matter of functional relationships, a student's ability to translate from one form of representation to another is seen as a central competence. In the course of the HEUREKO project (heuristic work with representations of functional relationships and the diagnosis of mathematical competencies of students), a theoretical competence…

This publication presents estimates of apprentice and trainee activity in Australia for the September quarter 2012. The figures in this publication are derived from the National Apprentice and Trainee Collection no.74 (December 2012 estimates). The most recent figures in this publication are estimated (those for training activity from the March…

The main purposes of this study were to investigate, by means of simulation: (1) whether the difference likelihood ratio chi-square statistic (G2-dif) for comparing item response theory (IRT) models is asymptotically distributed as a chi-square distribution; and (2) the accuracy rate of applying G2-dif in selection of nested IRT models. Two…

Results of a comparative study of F and Q tests, in a randomized block design with one replication per cell, are presented. In addition to these two procedures, a multivariate test was also considered. The model and test statistics, data generation and parameter selection, results, summary and conclusions are presented. Ten tables contain the…

A comparative study of the cost effectiveness of retrospective manual and on-line bibliographic searching is described. Individual task times for question analysis, searching, photocopying, shelving and output distribution were measured, and component costs for labor, information, reproduction, physical space and telecommunications calculated. The…

Describes the two basic approaches to the calculation of term discrimination values for automatic indexing. The results of an experiment that investigated the differences between algorithms of these two approaches in terms of their impact on the discrimination value model are reported and discussed. (13 references) (Author/CLB)

Presents two new algorithms for performing arithmetic coding without employing multiplication and discusses their implementation requirements. The first algorithm, suitable for an alphabet of arbitrary size, reduces the worst case excess length to under 0.8%. The second algorithm, suitable only for alphabets of less than 12 symbols, allows even…

New methods for comparing the medians corresponding to independent treatment groups are suggested. Procedures are based on the estimator of F. Harrell and C. Davis in conjunction with a modification and extension of the bootstrap calibration technique suggested by W. Loh. Data from two groups provide an illustration. (SLD)

Describes three models for probabilistic indexing, all based on the Darmstadt automatic indexing approach, and presents experimental evaluation results for each. The discussion covers the improved retrieval effectiveness of probabilistic indexing over binary indexing, and suggestions for using this automatic indexing method with free text terms.…

In a simulation study, factor analysis and multidimensional item response theory (IRT) models are compared with respect to estimates of item parameters. For multidimensional data, a common factor analysis on the matrix of tetrachoric correlations performs at least as well as the multidimensional IRT model. (SLD)

Two methods of analyzing nonorthogonal (uneven cell sizes) cross-classified data sets are compared. The methods are direct standardization and the general linear model. The authors illustrate when direct standardization may be a desirable method of analysis. (JKS)

Analyzes the properties of genetic sequences that cause the failure of classical algorithms used for data compression. A lossless algorithm, which compresses the information contained in DNA and RNA sequences by detecting regularities such as palindromes, is presented. This algorithm combines substitutional and statistical methods and appears to…

In presenting lessons in music theory by computer-assisted instruction, response-sensitive programing results in greater achievement than response-insensitive programing. (Author)

Five models which perform search tasks of the Data Base Access and Search Environment (DBASE) are presented and used for comparison with subject search performance--unconstrained (rule-based, decision theoretic) and constrained (optimal rule-based, rule-based, probabilistic rule-based). Previous experiments and the modeling approach are briefly…

This study estimates the proportion of academic and public library acquisitions in the United Kingdom for which a UK MARC record is available at the time of cataloging. A beta-binomial model is used to attribute standard errors to each estimate and to compare differences between the two types of libraries. (Author/LRW)