Discusses the application of statistical sampling to the compiling of reference-desk statistics, and describes a technique that uses the Pearson correlation procedure of SPSS (Statistical Package for the Social Sciences) to determine appropriate sampling periods for keeping reference desk statistics at the University of Missouri at St. Louis. (FM)

Estimates of sample size requirements for 2 X 2 tables, derived from three approximate formulae, were evaluated by comparison with exact calculations. Although different, the estimates derived from all three formulae were judged adequate for most practical purposes, with the most accurate results being obtained from Cohen's formula. (Author/JKS)

Problems of sampling error and accumulated rounding error in canonical variate analysis are discussed. A new technique is presented which appears to be superior to canonical variate analysis when the ratio of variables to sampling units is greater than one to ten. Examples are presented. (Author/JKS)

A large sample technique attributed to L. Marascuilo, based on the multiple comparison technique of H. Scheffe, was programmed with the Statistical Analysis System (SAS), focusing on comparisons among independent binomial samples. Use of the SAS program is discussed. (SLD)

Describes the Web Characterization Project that characterizes the use of metadata in Web documents by extracting a valid sample. Discusses Web resource discovery and description; sampling methods; metadata and embedded document description; HTML; Dublin Core metadata elements; and home pages versus internal Web pages. (Author/LRW)

Proposed a new asymptotic formula for estimating the sampling variance of a correlation coefficient corrected for unreliability and range restriction. A Monte Carlo simulation study of the new formula results in several positive conclusions about the new approach. (SLD)

Bootstrap methodology is presented that yields approximations of the sampling variation of redundancy estimates while assuming little a priori knowledge about the distributions of these statistics. Results of numerical demonstrations suggest that bootstrap confidence intervals may offer substantial assistance in interpreting the results of…

Sampling theory for the intraclass reliability coefficient, a Spearman-Brown extrapolation of alpha to a single measurement for each examinee, is less recognized and less cited than that of coefficient alpha. Techniques for constructing confidence intervals and testing hypotheses for the intraclass coefficient are presented. (SLD)

Examined Type I error rates and power for four tests for treatment control studies in which a larger treatment mean may be accompanied by a larger treatment variance and examined these aspects of the independent samples "t" test and the Welch test. Evaluated each test and suggested conditions for the use of each approach. (SLD)

This study utilized a rating scale and random sampling of Connecticut school speech-language pathologists about their preprofessional education and current knowledge of autism spectrum disorders (ASD). The participants had a minimal amount of preprofessional academic or clinical preparation in ASD, and no differences were found in how…

All differential item functioning (DIF) methods require at least a moderate sample size for effective DIF detection. Samples that are less than 200 pose a challenge for DIF analysis. Smoothing can improve upon the estimation of the population distribution by preserving major features of an observed frequency distribution while eliminating the…

This article examines theoretical and empirical issues related to the statistical power of impact estimates for experimental evaluations of education programs. The author considers designs where random assignment is conducted at the school, classroom, or student level, and employs a unified analytic framework using statistical methods from the…

This article highlights the problem of omitted variable bias in research on the causal effect of financial aid on college-going. I first describe the problem of self-selection and the resulting bias from omitted variables. I then assess and explore the strengths and weaknesses of random assignment, multivariate regression, proxy variables, fixed…

Background: A literature search found five empirical studies of psychological treatment for adults with ADHD, out of 1,419 articles on ADHD in adults. Practice guidelines to date all recommend multimodal intervention, given that a significant number of patients cannot tolerate, do not respond to, or fail to reach optimal outcomes with medication…