Presents a secondary classroom investigation into mathematical modeling techniques with the graphing calculator using a match stick puzzle. Geometric models, through their corresponding area formulas, are constructed, tested, and analyzed graphically to fit specified problem conditions. (Author/MKR)

Notes advantages of using dynamic models to understand cognitive functioning: (1) they are specifically intended to represent changes that systems undergo as they evolve; (2) they can capture change in a continuous fashion; (3) they can account for development of behavior that appears orderly at times and disorderly at others, and (4) chaotic…

Recommends that analysts (1) use conventional meta-analytic statistics when testing for moderator variables; (2) perform tests between mean effect sizes; and (3) continue to perform model tests in meta-analyses for which study outcomes are already consistent if they have theoretical expectations about moderators. (RS)

A modification of the TUCKALS3 algorithm is proposed that handles three-way arrays of order I x J x K for any I. The reduced work space needed for storing data and increased execution speed make the modified algorithm very suitable for use on personal computers. (SLD)

Presents a general mathematical model of the diffusion of innovations that incorporates mass media and interpersonal influence. Suggests that policymakers can use diffusion models to evaluate the effectiveness of media versus interpersonal campaigns, make comparisons between subgroups, and evaluate the effect of a policy. (RS)

Notes that methods for teaching intercultural communication skills are frequently based on identifying norms of communication in different cultures. Creates a parallel distributed processing (PDP) model, which is used to demonstrate the inadequacy of this normative approach to training. Discusses implications for the conduct of intercultural…

Replies to Guttentag's commentary on Brainerd and others' research on forgetting. Discusses measurement of forgetting, differentiation of storage from retrieval factors, and ramifications of findings for strategic or process theories of memory development. Considers the role of research on forgetting in child development research. (BC)

Conceptual rationales from five research contexts are presented, which all posit unmeasured variables that interact with observed independent variables to produce a complete model of the dependent variable. Strategies for overcoming related difficulties are outlined, including increased longitudinal assessment, oversampling of levels of…

D.V. Budescu and J.L. Rogers (1981) proposed a method of adjusting correlations of scales to eliminate spurious components resulting from the overlapping of scales. Three reliability correction formulas are derived in this article that are based on more tenable assumptions. (SLD)

Reviews the literature on Bradford's law (i.e., an empirical relationship describing the distribution of scholarly articles in relevant journals). A model for the distribution of articles, based on random partitioning, is presented; and a mathematical formulation for a law of scattering is derived. The relationship of the model to Bradford's law…

A unified treatment is presented for conditions that should allow detection of measurement bias using statistical procedures involving only observed or manifest variables. Computational results demonstrate that methods for studying bias that rely exclusively on manifest variables are not generally diagnostic of the presence or absence of…

Methods for assessing collapsibility in regression problems are described, including possible extensions to the class of generalized linear models. These procedures, with terminology borrowed from the contingency table field, can be used in experimental settings or nonexperimental settings where two models viewed as alternative explanations are…

Describes the use of time-lapse photographs of a running cat as a model to investigate the concepts of function and derivative in a college calculus course. Discusses student difficulties and implications for teachers. (MKR)

Describes a detailed algorithm for fast text compression. Related to the PPM (prediction by partial matching) method, it simplifies the modeling phase by eliminating the escape mechanism and speeds up coding by using a combination of quasi-arithmetic coding and Rice coding. Details of the use of quasi-arithmetic code tables are given, and their…

Describes the design of optimal tree-structured vector quantizers that minimize the expected distortion subject to cost functions related to storage cost, encoding rate, or quantization time. Since the optimal design problem is intractable in most cases, the performance of a general design heuristic based on successive partitioning is analyzed.…