Explored are the distributions of residual components in two model systems. A system of components with exponentially distributed lifetimes and the two-dimensional "leaf model" in which objects fall on a plane with positions independent and normally distributed are discussed. Included are the definition, application, computations, and theorem. (KR)

Surveys in which one can observe--after sample selection--that each sample member belongs to one or more aggregations are considered. A formula for the probability that a given aggregation contains at least one sample member is applied to eighth grade data from the National Educational Longitudinal Study of 1988 (NELS:88). (TJH)

Two frame-of-reference rater training approaches were compared for effects on reliability and accuracy of cutoff scores generated by 21 raters using Angoff methods on tests taken by 155 undergraduates. Both approaches result in higher interrater reliability and more accuracy than does a non-frame-of-reference method. (SLD)

Applies chaos theory to complex social organization, beginning with a mathematical definition of chaos. Shows how a nonlinear equation might be used to describe organization. The conclusion section identifies three approaches to analyzing chaos in social organization: metaphorical analysis, mathematical modeling, and data collection. (36…

A technique for the numerical identification of bacteria using normalized likelihoods calculated from a probabilistic database is described, and the principles of the technique are explained. The listing of the computer program is included. Specimen results from the program, and examples of how they should be interpreted, are given. (KR)

Discussed are solutions to the problem "What is the expected number of rolls for the total first to exceed 6?" Several algebraic solutions are presented. A computer program which may be used to simulate this problem is included. (CW)

This paper provides a method for analyzing data consisting of event sequences and covariate observations associated with Markov chains. The objective is to use the covariate data to explain differences between individuals in the transition probability matrices characterizing their sequential data. (TJH)

This article shows how the methods of survival analysis (also known as event history analysis) lend themselves to the study of the timing of educational events. Using examples from teacher attrition and student dropout research, survival methods are introduced for building statistical models of the risk of event occurrence over time. (Author/SLD)

Revealing or visualizing the thinking involved in making clinical decisions is a challenge. A case study is presented with a visual implement for sharing the diagnostic process. This technique adapts the Bayesian approach to the case presentation. Pretest probabilities and likelihood ratios are gathered to obtain post-test probabilities of every…

In 2 eye-movement experiments, the authors tested whether transitional probability (the statistical likelihood that a word precedes or follows another word) affects reading times and whether this occurs independently from contextual predictability effects. Experiment 1 showed early effects of predictability, replicating S. A. McDonald and R. C.…

Analysis of variance (ANOVA), a technique included in many introductory statistics courses, analyzes the relationship between a quantitative dependent variable and one or more independent qualitative variables. The nature of the relationship is expressed in a model with unknown parameters. Many textbooks emphasize the mechanics of the technique…

The current study analyzed a subset of the experimental data collected by Berk, Ladd, Graziano, and Baek (2003) to test whether different intensities of incarceration make inmates more criminal while incarcerated. There were 561 male inmates whose equivalent classification scores indicated they had the same level of risk to commit institutional…

The study uses individual data from the Canadian Labour Force Survey to consider economic factors in university participation decisions by persons aged 17-24 from 1976 to 2003. The level of real tuition is one economic factor that may affect the university participation decision. There is also regional variation in the opportunity cost of…

Research in goal theory has often relied on the general linear model, ignoring some central assumptions of the theoretical framework under investigation. The purpose of the two studies reported here was to illustrate how the Rasch model can supplement traditional statistical analyses when evaluating the effects of goal orientations on persistence.…

This article describes an innovative lesson that uses the biography "Barbara McClintock: Alone in her Field" (Heiligman, 1994) to integrate genetics, literature, and mathematics as a context for students to investigate patterns on Indian corn. This two-day lesson requires students to estimate, collect data, identify and describe patterns,…