Langmuir's model is studied for the situation where epsilon is independently and identically normally distributed. The "Y/x" versus "Y" plot had a 90% mid-range that did not contain the true curve in a vast portion of the range of "x". The "1/Y" versus "1/chi" plot had undefined expected values,…

This paper explains how commonality analysis (CA) can be conducted using a specific Statistical Analysis System (SAS) procedure and some simple computations. CA is used in educational and social science research to partition the variance of a dependent variable into its constituent predicted parts. CA determines the proportion of explained…

Use of "special" orthonormal mean contrasts and mean contrast variances can help educational researchers interpret a wide variety of repeated measures data. Most statistical packages allow educational researchers to test for differences across repeated measures using both the univariate mixed model F test and a multivariate test.…

In clinical trials, adaptive allocation means that the therapies assigned to the next patient or patients depend on the results obtained thus far in the trial. Although many adaptive allocation procedures have been proposed for clinical trials, few have actually used adaptive assignment, largely because classical frequentist measures of inference…

Concern has been expressed over the item response theory (IRT) assumption that a person's ability can be estimated in a unidimensional latent space. To examine whether or not the response to an item requires only a single latent ability, unidimensional ability estimates were compared for data generated from the multidimensional item response…

Previous economic models suggested that, due to the high channel capacity of cable technology and its capability of pricing television programs directly to the viewers, its diffusion would promote specialized "narrow appeal" programming designed to serve relatively small audience segments. While this has clearly occurred, these models do…

The purpose of this study was to develop a model for the distribution of authorships--based on the initial hypothesis that the distribution of authorships follows a shifted Waring distribution--and to test the derived model and some other discrete probability models for goodness-of-fit against empirical data. Bibliographic data from 15 abstracting…

A formula is derived for the asymptotic standard error of a true-score equating by item response theory (IRT). The equating method is applicable when the two tests to be equated are administered to different groups along with an "anchor test." Numerical standard errors are shown for an actual equating 1) comparing the standard errors of…

This paper attempts to provide some initial information about the use of a variety of item response theory (IRT) models in the item selection process; its purpose is to compare the information curves derived from the selection of items characterized by several different IRT models and their associated parameter estimation programs. These…

Needs assessment almost always focuses on the assessment of change, change from the real to the ideal, present to future, actual to expected, and so on. As a result, most definitions of need can be represented by a mathematical-style change formula. However, most presentations of the concept of change do not completely represent the complexity of…

The author contends that model misspecification can occur even after researchers have selected the generally most appropriate class of methods, or general linear model techniques. It is suggested specifically that canonical correlation analysis may provide more meaningful results, as compared with regression, particularly if analysis is augmented…

To learn something of the experience Canadian administrators have had in the use of quantitative models, a brief questionnaire was sent to 126 Canadian educational agencies. Presents some categorical statements about the experience reported, and gives author's opinion on what has caused the present condition. (Author/JF)

Explores the relevance of some of the methodologies of systems engineering to problems in the social sciences, especially the dynamics of domestic and international conflict. Describes an initial exercise in modeling domestic conflict in terms of State equations. Implications for education. (Author/WM)

Three techniques for estimating Kuder Richardson reliability (KR20) coefficients for incomplete data are contrasted. The methods are: (1) Henderson's Method 1 (analysis of variance, or ANOVA); (2) Henderson's Method 3 (FITCO); and (3) Koch's method of symmetric sums (SYSUM). A Monte Carlo simulation was used to assess the precision of the three…

This study attempts to determine which media-exposure models available today are the best. A survey of the literature of the last 20 years is used to provide the basis for assessment of the state of the art of media planning and to draw distinctions between the implicit, naive, subjective, and sophisticated media-exposure models. Discussion of the…