The article investigates the patterns that arise in the convergence of numerical methods, particularly those in the errors involved in successive iterations, using data analysis and curve fitting methods. In particular, the results obtained are used to convey a deeper level of understanding of the concepts of linear, quadratic, and cubic…

Hidden Markov models (HMMs) are widely used in bioinformatics, speech recognition and many other areas. This note presents HMMs via the framework of classical Markov chain models. A simple example is given to illustrate the model. An estimation method for the transition probabilities of the hidden states is also discussed.

This paper reports on studies of the deterministic and stochastic behaviours of a predator-prey system with prey-dependent response function. The first part of the paper deals with the deterministic analysis of uniform boundedness, permanence, stability and bifurcation. In the second part the reproductive and mortality factors of the prey and…

The G index is a measure of the similarity between individuals over dichotomous items. Some tests for the G-index are described. For each case an example is included. (Author/GK)

Estimates a college-attendance equation for a common set of students (from the High School and Beyond Survey) using three popular econometric specifications: the multinomial logit, the ordered probit, and the bivariate probit. Estimated marginal effects do not differ significantly across the three specifications. Choice of specification may not…

The average citation per article in chemistry by age of citation is related to the Poisson frequency distribution. This provides a formula for calculation of a half-life for chemistry which depends on the structure of the research front exhibited in the literature. (Author/FM)

In 1984 "Economics of Education Review" paper, E. Bell indicates that, when capital markets are imperfect in a certain sense, demand for education may not always be directly related with present net value of education. This study shows Bell's paradox is possible under the alternative definitions of capital market imperfections and…

Explores whether flexible nonlinear models (including neural networks and genetic algorithms) can reveal otherwise unexpected patterns of relationship in typical school-productivity data. Applying three types of algorithms alongside regression modeling to school-level data in 183 elementary schools proves the hypothesis and reveals new directions…

Flowing granular mixtures in rotating cylindrical drums arise in numerous industrial settings and are of great technological significance worldwide. To date, the development of a robust mathematical model for this process remains an open research problem. However, simple mathematical models may be developed that capture some of the underlying…

Multivariate generalizability techniques are used to bridge the gap between psychometric constraints and the tables of specifications needed in test development. Techniques are illustrated with results from the American College Testing Assessment Program. (Author/PN)

Examines data from California from the 1850 opening of the prison system to 1970. Finds no evidence to support the hypothesis that, for a given society over time and in the absence of major societal upheaval, the proportion of people subjected to punishment by the state closely approximates a constant. (Author/GC)

Analyzes propensity of business school alumni to give cash donations to their alma mater. Estimates a utility maximization model, using logistic regression and survey sample data of 1956-90 graduates of a large U.S public research university. Giving probability is strongly correlated with specific majors, time since graduation, other factors.…

An inventory replenishment policy is developed for a deteriorating item and price-dependent demand. The rate of deterioration is taken to be time-proportional and the time to deterioration is assumed to follow a two-parameter Weibull distribution. A power law form of the price dependence of demand is considered. The model is solved analytically…

Results from numerous school- and teacher-effectiveness studies suggest that variation between classes is more significant than variation between schools, though evidence often seems contradictory. This article considers why different studies generate different findings, identifies key study design issues, and relates these observations to…

Applies neural network methods for forecasting 1991-95 per-pupil expenditures in U.S. public elementary and secondary schools. Forecasting models included the National Center for Education Statistics' multivariate regression model and three neural architectures. Regarding prediction accuracy, neural network results were comparable or superior to…