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…

"Who has been to Dairy Queen® and purchased a Blizzard?®" Ms. Bosetti asked her students. During the summer, Bosetti had seen many of her former and future students at the local Dairy Queen enjoying Blizzard desserts and wondered, "Which Blizzard size is the best value?" She used this context for a ratios and proportions task…

Amazon, Walmart, and other large-scale retailers owe their success partly to efficient inventory management. For such firms, holding too little inventory risks losing sales, whereas holding idle inventory wastes money. Therefore profits hinge on the inventory level chosen. In this activity, students investigate a simplified inventory-control…

This study evaluates the effects of an intervention aimed at improving representational flexibility in linear-function problems. Forty-nine students aged 13-16 participated in the study. A pretest-intervention-posttest design with an experimental and control group was used. At pretest, both groups solved a choice test, where they could freely…

It is shown that Trueswell's empirical 80/20 rule arises from type of stochastic model for library loans presented by Burrell and Cane. Particular attention is paid to previously suggested uses of rule in identifying "core collection" for library noting that length of time period is of crucial importance. (20 references) (EJS)

Structural models that yield circumplex inequality patterns are reviewed, focusing on a model developed by T. W. Anderson (1960). A modification is proposed to this model to allow for negative correlations. This model may be reparameterized as a factor analysis model with nonlinear constraints on the factor loadings. (SLD)

The intent of this paper is to generalize the min and max clustering procedures in such a way that the assumption of a symmetric similarity measure is unnecessary. (Author)

This mathematical model is intended to be a tool for the monitoring of the bargaining process and to provide the ability to predict the form of bargaining outcomes given certain initial conditions. It applies to situations in organizations in which the conflict between the expressed desires of interest groups are settled by a bargaining process…

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…

Review of recent developments in statistical theories for social sciences highlights Haitun's statistical distributions, Laplace's "Law of Succession" and distribution, Laplace and Bradford analysis of book-index data, inefficiency of frequency distribution analysis, Laws of Bradford and Zipf, natural categorization, and Bradford Law and…

Presents an activity on linear functions that is designed to help students become familiar with the graphs, equations, and tables of these functions while focusing on issues related to cost, revenue, and profit. (ASK)

This article describes a lesson unit in which students constructed tables and graphs to represent the growth of different trees. Students then compared the graphs to develop an understanding of slope.

Working from the premise that for any given periodical title there is some frequency of use at which it becomes cheaper for a library to acquire the publication than to borrow it, this report presents a mathematical model for estimating the costs of options associated with acquiring periodicals. Cost elements included in the model are initial…

Four bootstrap methods are identified for constructing confidence intervals for the binomial-error model. The extent to which similar results are obtained and the theoretical foundation of each method and its relevance and ranges of modeling the true score uncertainty are discussed. (SLD)

Ignorance of the characteristics of a mixed population may lead to bias in a summary measure of a phenomenon. A test based on sample kurtosis is demonstrated by a simulation study to be more powerful than six other known tests in detecting a class of mixed normal distributions. (SLD)