Discussion of models for library circulation data highlights a new statistical prediction model that creates a flexible regression curve. Linear graphs that result from previous models are discussed, bivariate discrete distributions are explained, and graphs that show library circulation for one year at a time are presented. (nine references) (LRW)

Illustrates that the Poisson-lognormal model provides good fits to a diverse set of distributions commonly studied in bibliometrics and scientometrics. Topics discussed include applications to the empirical data sets related to the laws of Lotka, Bradford, and Zipf; causal processes that could generate lognormal distributions; and implications for…

Describes a study that was conducted to model the navigation patterns followed by users when retrieving information in hypertext systems. The development of two frequency distribution models is explained, the influence of search tasks on path patterns is discussed, and further research is described. (Contains 17 references.) (LRW)

The adequacy of multidimensional trait and item parameters using multidimensional item response theory analysis was studied through simulation using different degrees of correlation between two trait dimensions and the existence of a restricted trait on the second dimension. Conditions allowing adequate recovery of trait and item parameters are…

The delta method was used to derive standard errors (SES) of the Levine observed score and Levine true score linear test equating methods using data from two test forms. SES derived without the normality assumption and bootstrap SES were very close. The situation with skewed score distributions is also discussed. (SLD)

A flexible class of stochastic mixture models is introduced and illustrated for analysis and interpretation of individual differences in recurrent choice and other types of count data. These models are derived by specifying elements of the choice process at the individual level. An easy-to-implement algorithm is presented for parameter estimation.…

Discusses the influence of publication delays on the aging of scientific literature and explains how the undisturbed aging function and the publication delay combine to give the observed aging function through a mathematical operation called convolution. Shows the convolution of various distributions and considers a paradox between theory and real…

Describes a study conducted in a Taiwan hospital library that explored the in-house use age distribution of journals, their citation age distribution, and the difference between them. Discusses use of the Kolmogorov-Smirnov test, which showed that the use age distribution does not fit the citation age distribution. (Author/LRW)

Describes a hands-on demonstration of the concept of the sampling distribution of the mean using M&M's candy. Compares the effectiveness of the candy demonstration with that of a comparable demonstration using a textbook example. Reports that students exposed to the candy example performed better on a subsequent examination. (DSK)

Studied three measures of task and ego achievement goal orientations in terms of factorial and construct validity, internal consistency reliability, and distributional characteristics. Results for 393 undergraduates suggest that the Patterns of Adaptive Learning Survey scales fared better than the other 2 in terms of distributional…

Theoretical null distributions of several fit statistic have been derived for paper-and-pencil tests. Examined whether these distributions also hold for computerized adaptive tests through simulation. Rates for two statistics studied were found to be similar in most cases. (SLD)

Uses the random-number generator and list features on the TI-83 graphing calculator to generate lists of sample means to help illustrate the concepts discussed in introductory statistics courses. (ASK)

Evaluated the distribution of person fit within the computerized-adaptive testing (CAT) environment through simulation. Found that, within the CAT environment, these indexes tend not to follow a standard normal distribution. Person fit indexes had means and standard deviations that were quite different from the expected. (SLD)

Applies a method for measuring scientific author productivity to a wide variety of fields. Results show that each individual's production is constant over time, the time-period fluctuations follow the Poisson distribution, the productivity varies widely across individuals, and the distribution of productivity follows the exponential distribution.…

We present statistical analyses of the large-scale structure of 3 types of semantic networks: word associations, WordNet, and Roget's Thesaurus. We show that they have a small-world structure, characterized by sparse connectivity, short average path lengths between words, and strong local clustering. In addition, the distributions of the number of…