An alternative formulation of the multigroup common factor model with minimal uniqueness constraints is considered. This alternative formulation is based on a simple identification constraint that is related to the standard maximum likelihood constraint used in single-group common factor analysis. It is argued that the alternative formulation…

Eggerth and Andrew (2006 [this issue]) provide a valuable contribution to researchers and practitioners using the C index to measure congruence when person or environment codes contain fewer than three letters. However, the computational procedures outlined by Eggerth and Andrew may be more complex than they need be. A simpler alternative to…

Kappa (Cohen, 1960) is a popular agreement statistic used to estimate the accuracy of observers. The response of kappa to differing baserates was examined and methods for estimating the accuracy of observers presented. Results suggest that setting a single value of kappa as "minimally acceptable" (i.e., a criterion value) is not useful in ensuring…

The absorbance decay of hexacyanoferrate(III) as a function of time shows a progressive deviation from zero to first order. This variation follows an experimental rate law that has been analyzed. The change in reaction order is due to a change in the relative rate of substrate oxidation with respect to that of catalyst regeneration. (Contains 2…

This article employs the Archimedean method of estimating the value of pi within an inscribed pentagon. We show how to write these approximations in terms of the golden ration.

Methods for planning sample size (SS) for the standardized mean difference so that a narrow confidence interval (CI) can be obtained via the accuracy in parameter estimation (AIPE) approach are developed. One method plans SS so that the expected width of the CI is sufficiently narrow. A modification adjusts the SS so that the obtained CI is no…

Accurate and accessible expressions for the probability of having a matching birthday are obtained by using Stirling's formula and Taylor series. For interest, the results are applied to the planets of our solar system.

Study of the performance of nearly 2,000 students in grades 2 through 9 on a variety of mental computation tasks using visual and oral presentation found a wide variation in performance within the sample of each country at each grade level. (33 references) (MKR)

Magnitude of effect (ME) statistics are an important alternative to statistical significance. Why methodologists encourage the use of ME indices as interpretation aids is explained, and different types of ME statistics are discussed. The basic concepts underlying effect size measures are reviewed, and how to compute them from published reports…

Item and test analyses can be used to revise and improve both test items and the test as a whole. Recommendations for item and test analysis practices as they are reported in commonly used measurement textbooks are summarized. A heuristic data set is used to illustrate test and item analysis practices. Techniques developed in this paper are…

This paper dramatizes the complexity and the problems involved in calculating the rates of student dropouts from school. To compare the dropout formulas used by various agencies, states, and local school systems, responses from a national survey are presented and used to calculate a range of dropout rates for the Austin (Texas) public schools. By…

This study derived an expectation-maximization (EM) algorithm for estimating the parameters of multidimensional item response models. A genetic algorithm (GA) was developed to be used in the maximization step in each EM cycle. The focus of the EM-GA algorithm developed in this paper was on multidimensional items with "mixed structure."…

Fourteen topics are discussed that need to be included in the curriculum to make it possible for students to successfully take full advantage of the calculator and its capabilities. These include: underflow, overflow, estimation, scientific notation, powers of ten, rounding, and truncation. (MP)

Following a brief history of Logo, BASIC, and Pilot programing languages, common educational programing tasks (input from keyboard, evaluation of keyboard input, and computation) are presented in each language to illustrate how each can be used to perform the same tasks and to demonstrate each language's strengths and weaknesses. (MBR)