Homoscedasticity is an important assumption of linear regression. This paper explains what it is and why it is important to the researcher. Graphical and mathematical methods for testing the homoscedasticity assumption are demonstrated. Sources of homoscedasticity and types of homoscedasticity are discussed, and methods for correction are…

Although the topological index does not uniquely correspond to the individual structure of a graph, it roughly represents the topological nature of the graph. Examples are given for using the topological index as a first sorting device for coding and retrieving structures, especially of fused polycyclic systems. (14 references) (Author/NH)

Describes the procedure for determining the readability of a book or article in terms of approximate grade level. (CHC)

Concepts of ordinal network representation are discussed. Notation (the type of data that can be represented) and the type of representation given are reviewed. The idea of reduced ordinal networks is explored; and the algorithm, uniqueness results, and error handling problems are presented. Examples of data analysis are included. (SLD)

Results of this simulated study indicate that, when unidimensional stimulus sets are scaled in two dimensions using a rational starting configuration, the nature of the two-dimensional configuration can indicate the general form of the function mapping psychological dissimilarity--represented as distance in the scaling model--onto the observed…

The manner in which the conditional independence graph of a multiway contingency table affects the fitting and interpretation of the Goodman association model and of correspondence analysis is considered. Estimation of row and column scores is presented through a framework that includes both models. (SLD)

Introduces a new inferential test for acyclic structural equation models (SEM) without latent variables or correlated errors. The test is based on the independence relations predicted by the directed acyclic graph of the SEMs, as given by the concept of d-separation. A wide range of distributional assumptions and structural functions can be…

Describes a study in which secondary school students were called upon to read and interpret documents containing images of real-time kinematics graphs specially designed to address common learning problems and minimize iconic difficulties. Makes suggestions regarding the acquisition of some specific capabilities that are needed to avoid…

This study analyzes the interpretive activities of scientists related to familiar and unfamiliar graphs. The analyses show that when scientists were familiar with a graph, they read it transparently and thereby leapt beyond the material basis to the thing the graph is said to be about. In contrast, when scientists were less familiar with the…

Quantitative literacy, the ability to discriminate between good and bad data, the disposition to use quantitative information to think through complex problems are capacities that educators across fields should be helping students develop. Burke leads the reader to this conclusion through an extended example of income distribution, clarified and…

We believe a lack of transparency undermines both the credibility of, and interest in, stated choice studies among policy makers. Unlike articles reporting the results of contingent valuation studies, papers in the stated choice literature rarely present simple tabulations of raw response data (that is, a table or graph showing the percentage of…

This paper, the second of a two part article, expands on an idea that appeared in literature in the 1950s to show that by restricting the domain to those complex numbers that map onto real numbers, representations of functions other than the ones in the real plane are obtained. In other words, the well-known curves in the real plane only depict…

The present study investigated the extent to which providing students with individualized performance feedback informed and directed their learning behavior. Individualized performance feedback was delivered to students using curriculum-based measurement progress indicators, either as a visual representation of ongoing performance in the form of a…