Estimated Type I error rates for three tests that compare means by testing data from two independent samples: (1) the independent samples "t" test; (2) B. Welch's approximate degrees of freedom test (1938); and (3) G. James's second-order test (1951, 1954). Results provide guidance about the total sample sizes required for controlling…

Although the use of "text coverage" to measure the intelligibility of reading materials is increasing in the field of vocabulary teaching and learning, to date there have been few studies which address the methodological variables that can affect reliable text coverage calculations. The objective of this paper is to investigate how differing…

Cooking and tasting chicken soup in three different pots of very different size serves to demonstrate that it is the absolute sample size that matters the most in determining the accuracy of the findings of the poll, not the relative sample size, i.e. the size of the sample in relation to its population.

This limited study provided the first step in exploring existing information mined from a statewide community college Student Information System (SIS) regarding blended, online, and face-to-face instructional methods courses. The purpose was to explore the retention claims of blended instructional method courses, retention of face-to-face and…

To help assess the effects of school-based random drug testing programs, the U.S. Department of Education's Institute of Education Sciences (IES) contracted with RMC Research Corporation and Mathematica Policy Research to conduct an experimental evaluation of the Mandatory-Random Student Drug Testing (MRSDT) programs in 36 high schools within…

This study examined the effectiveness of a supervised mentoring program designed to improve the academic achievement of 834 low-income elementary and secondary school students in Seoul, South Korea. When compared to the control group, both elementary and middle school students exposed to the mentoring program improved in mathematic and reading…

The synthetic function, which is a weighted average of the identity (the trivial linking function for forms that are known to be completely parallel) and a traditional equating method, has been proposed as an alternative for performing linking with very small samples (Kim, von Davier, & Haberman, 2006). The purpose of the present study was to…

A novel assignment exercise is described, in which students use a dictionary to estimate the size of their vocabulary. This task was developed for an introductory statistics service course, although it can be modified for use in survey sampling courses. The exercise can be used to simultaneously assess a range of core statistics skills: sample…

The major objective of this study was to investigate the effects of non-normality on Type III error rates for ANOVA F its three commonly recommended parametric counterparts namely Welch, Brown-Forsythe, and Alexander-Govern test. Therefore these tests were compared in terms of Type III error rates across the variety of population distributions,…

Mokken scale analysis can be used for scaling under nonparametric item response theory models. The results may, however, not reflect the underlying dimensionality of data. Various features of Mokken scale analysis--the H coefficient, Mokken scale conditions, and algorithms--may explain this result. In this article, three new H-based objective…

Many out-of-school time programs want to learn more about how the children and youth they serve are faring. Outcome evaluations allow programs to do just that. This brief provides a basic review of outcome evaluations, discusses why they are important and when they are useful, and presents guidelines, strategies, and techniques for their use in…

In 4 studies, the authors examined the hypothesis that the structure of the informational environment makes small samples more informative than large ones for drawing inferences about population correlations. The specific purpose of the studies was to test predictions arising from the signal detection simulations of R. B. Anderson, M. E. Doherty,…

Purpose. The purpose of this study was to determine if there was a significant difference in academic achievement on the California Standards Tests (CSTs) in English and mathematics of students enrolled in the California Partnership Academy compared to the nonacademy population. A second purpose was to analyze the percentage of first-time passage…

Although there is a substantial literature on factors that encourage college students' success, Light's 2001 Harvard study, "Making the Most of College," represents the largest qualitative study in a highly quantitative gathering. There is little qualitative research on college-student success, especially that of transfer students. To discover how…

If students are to understand inferential statistics successfully, they must have a profound understanding of the nature of the sampling distribution. Specifically, they must comprehend the determination of the expected value and standard error of a sampling distribution as well as the meaning of the central limit theorem. Many students in a high…