Staddon and Motheral derived a mathematical model of responding in concurrent variable-interval--variable-interval schedules. Their derivation ignores a fundamental aspect of the concurrent schedule contingency. A reinforcer can occur following two consecutive responses on the same schedule or following a switch between the two schedules.…

Heyman's major criticism (TM 504 810) of Staddon and Motheral's reinforcement maximization model is that it does not consider "local" and "interchangeover" interresponse times separately. We show that this separation may not be necessary. Heyman's apparent gain in comprehensiveness may not be worth the added complexity.…

In the study reported here a cost model of facility usage was constructed to assess the financial impact of alternative facility usage policies. Results of the study indicate that the financial benefits that accrue from increased facility utilization would likely be more than offset by increased costs. (Author)

This survey of current work on data base systems is divided into three main sectors: data models, data languages, and support for data base operations, including hardware for content addressing, data base machines, and software techniques for optimizing and evaluating group expressions. A 203-item bibliography is provided. (Author/JD)

An example demonstrates that Joreskog's suggested sufficient conditions for identifying unknown parameters in a confirmatory factor analytic model with correlated factors are not sufficient. Sufficient conditions are presented. (Author/JKS)

Assuming that subject responses rank order stimuli by preference, statistical methods are presented for testing the hypothesis that responses conform to a unidimensional, qualitative unfolding model and to an a priori stimulus ordering. The model is suitable for the analysis of structure in attitude responses, preference data, and developmental…

The Bayesian approach to setting passing points on credentialing examinations in the health fields is considered in the context of the Normal model, and examples are given to demonstrate the procedure. An application to a credentialing examination, to determine a rational passing point, is presented. (Author/MH)

The theory of plate tectonics is discussed as it relates to connection, purported to be the driving force involved in the movements of the earth's crust. (SA)

Focuses on recent research on currents and eddies of the earth's oceans. Special emphasis is given to instrumentation involved in studying the oceans. (SA)

Presents an examination of graphical displays of solutions to time-dependent Schrodinger equation modeling a laser-excited three-level atom. It suggests that an energy level may be regarded as virtual when it is detuned from resonance by more than two Rabi frequencies. (Author/HM)

A short course in probability and statistics for administrators and managers is described. Topics covered in one of the lecture sessions are discussed. (DT)

Inequalities in schooling may be seen in relation to two types of educational outcomes: quality and quantity (or achievement and attainment). The qualitative dimension, a major concern of Coleman, Campbell, Hobson, McPartland, Mood, Weinfeld, and York are considered first, followed by the Blau-Duncan and Wisconsin studies of years of schooling…

A sophomore-level course in applications of mathematics was designed to introduce students to the diversity of situations in which mathematical models are used. The course precedes the study of the calculus, and is composed of a sequence of modules. A problem-solving approach is used. (SD)

Demonstrates that the number of kilometers of highway in the U.S. tends to grow exponentially and discusses what can be done to modify this growth. (MLH)

Undergraduate and graduate students are often confused about several aspects of modeling physical systems. Describes an approach to address these issues using a single physical transport problem that can be analyzed with multiple mathematical models. (DKM)