A Monte Carlo experiment was conducted to investigate the performance of bootstrap methods in normal theory maximum likelihood factor analysis when the distributional assumption was satisfied or unsatisfied. Problems arising with the use of bootstrap methods are highlighted. (SLD)

In response to Leonard (EC 600 867), the article suggests that Leonard's idea that many language-impaired children merely represent the low end of the normal distribution of language ability does not eliminate neuropathology as one possible primary cause of language impairment. (Author/DB)

Reports on a study that examined the behavior of the journal productivity distribution curve over time using bibliographic references for research reports in chemistry and physics by Croatian authors over a 10-year period. Data characteristics of interest are described; and results regarding one-year distributions, changes in data characteristics,…

Corrects an error in the calculation of the Kolmogorov-Smirnov (KS) statistic when it is used to empirically confirm or deny the generalized Lotka's law. Examples from the literature are given of both correct and incorrect uses of the KS test and Lotka equations with cumulative distribution functions (CDFs). (six references) (LRW)

An approximate statistical test is derived for the hypothesis that the intraclass reliability coefficients associated with two measurement procedures are equal. Control of Type 1 error is investigated by comparing empirical sampling distributions of the test statistic with its derived theoretical distribution. A numerical illustration is…

Proposes a plotting position formula for the Pearson type III distribution in the analysis of historical flood information. Presents results of a numerical example using actual flood data to confirm the appropriateness of the plotting formula. (24 references) (MDH)

A systematic investigation of the Grice modeling scheme for response time (RT) clarifies fundamental notions about RT modeling. The analysis presented can be used to determine what in a certain RT model constitutes a set of empirically testable assumptions and what is merely an arbitrary choice of mathematical language. (SLD)

Because it is sensitive to variability and permits partitioning of a distribution into the tails and center, the Hedges and Friedman Index can be used to investigate gender differences in each partition. It should yield greater insight into the nature of between-gender differences, as its application to Feingold's 1992 data illustrates. (SLD)

Examines the applicability of Lotka's Law, negative binomial distribution, and lognormal distribution for institutional productivity in the same way as it is to authors and their productivity. Results indicate that none of the distributions are applicable for institutional productivity in engineering sciences. (Author/LRW)

Examined five Rasch-model-based item-fit indices in terms of their distributional properties and the power of detecting item bias or differential item functioning. Results indicate that, although these five standardized item-fit indices did not depart significantly from a normal distribution, the Type I error rates were not reasonable. (Author/SLD)

Concentrations of chemical substances and microorganisms are often averaged using geometric means. Argues that the arithmetic mean is a better choice for summarizing data because arithmetic means are unbiased, easier to calculate and understand, scientifically more meaningful, and more protective of public health. Results of a simulation study…

Provides and illustrates a method to compute the expected number of misclassifications of examinees using three-parameter item response theory and two state classifications (mastery or nonmastery). The method uses the standard error and the expected examinee ability distribution. (SLD)

Confidence intervals (CIs) give information about replication, but many researchers have misconceptions about this information. One problem is that the percentage of future replication means captured by a particular CI varies markedly, depending on where in relation to the population mean that CI falls. The authors investigated the distribution of…

Distinguishing between discrete and continuous latent variable distributions has become increasingly important in numerous domains of behavioral science. Here, the authors explore an information-theoretic approach to latent distribution modeling, in which the ability of latent distribution models to represent statistical information in observed…

In this paper, we consider some combinatorial and statistical aspects of the popular "Powerball" lottery game. It is not difficult for students in an introductory statistics course to compute the probabilities of winning various prizes, including the "jackpot" in the Powerball game. Assuming a unique jackpot winner, it is not difficult to find the…