P. A. Frazier, A. P. Tix, and K. E. Barron (2004) highlighted a normal theory method popularized by R. M. Baron and D. A. Kenny (1986) for testing the statistical significance of indirect effects (i.e., mediator variables) in multiple regression contexts. However, simulation studies suggest that this method lacks statistical power relative to some…

There has been relatively little discussion in the field of child language acquisition about how best to sample from children's spontaneous speech, particularly with regard to quantitative issues. Here we provide quantitative information designed to help researchers make decisions about how best to sample children's speech for particular research…

Concerned about reports of a 15% decline in HIV testing among high-risk youth in an earlier study in Pittsburgh, this study was initiated to explore reasons why young people are not getting tested for HIV, while gathering data on their respective level of risk taking behaviors. A total of 580 surveys were collected from youth aged between 14 and…

Background: The Thinking Styles Inventory--developed by Sternberg and Wagner based on Sternberg's (1988, 1997) earlier theory of mental self-government--was selected for the research in order to assess thinking styles of student teachers. Another reason is that the theoretical constructs, as well as the inventory generated from the theory, have…

In 1982, the Educational Testing Service (ETS) proposed to implement a new, complex design for the National Assessment of Educational Progress (NAEP). The major features of this design are described in "A New Design for a New Era" (Messick, Beaton, and Lord, 1983). The purpose of this document is to describe the actual implementation of…

Thirty-four papers on educational statistics which were presented at the 1971 AERA Conference are summarized. Six major interest areas are covered: (a) general information; (b) non-parametric methods; (c) errors of measurement and correlation techniques; (d) regression theory; (e) univariate and multivariate analysis; (f) factor analysis. (MS)

Researchers persist in using stepwise regression in spite of problems with this approach. As noted by B. Thompson (1995), three problems accompany the use of stepwise applications. The first is that computer packages may use incorrect degrees of freedom in their computations, resulting in a greater likelihood of obtaining a spurious statistical…

This paper describes an approach to item analysis that is based on the estimation of a set of response curves for each item. The response curves show, at a glance, the difficulty and the discriminating power of the item and the popularity of each distractor, at any level of the criterion variable (e.g., total score). The curves are estimated by…

The effectiveness of 19 methods of smoothing was investigated as those methods apply to the equipercentile method of test equating. Seven methods involved smoothing the score distribution before the tests were equated (presmoothing). Seven involved smoothing the resultant points after the equating (postsmoothing). Five methods involved combining…

The major emphasis of the National Longitudinal Study of the High School Class of 1972 (NLS) has been directed toward individuals in the 1972 high school graduating class. Consequently, sampling parameters were established to ensure student representation, and the bulk of data collected were individual-level data. School-level data exist on a…

In assessing educational equity among school districts, according to the authors, researchers should control for differences across districts in the prices of educational inputs. This paper tests a suggested index for one educational input, teacher salaries. The suggested teacher-salary index, based on a supply-and-demand model using 12 demand and…

This Environmental Protection Agency manual was developed to provide pollution biologists with the most recent methods for measuring the effects of environmental contaminants on freshwater and marine organisms. The sections of this manual include: (1) Biometrics; (2) Plankton; (3) Periphyton; (4) Macrophyton; (5) Macroinvertebrates; (6) Fish; and…

It is sometimes desirable to obtain an estimated total-test score for an individual who was administered only a subset of the items in a total test. The present study compared six methods, two of which utilize the content structure of items, to estimate total-test scores using 450 students in grades 3-5 and 60 items of the ll0-item Stanford Mental…

Analysis of covariance is examined for its usefulness in attribute-by-treatment interaction (ATI) research, where subjects are randomly assigned to treatments but not to levels of the attribute factor. Contrary to what might be expected, the use of a covariate does not confound the interpretation of the interaction between attribute and treatment,…