Discusses the idea that with larger cohorts of the very old, subjects in their 80s and 90s will be increasingly sought as respondents. Points out various steps that need to be taken to assure that this older group will be represented by the ailing as well as the healthy community residents. (Author/EJT)

Rosenthan's (1979) concept of fail-safe N has thus far been applied to probability levels exclusively. This note introduces a fail-safe N for effect size. (Author)

Examines assumptions underlying the employment of group means in communication research. Suggests a sample mean cannot be assumed to be a "good" statistic when the response vector represents different individuals' outcomes versus different outcomes of an individual. Notes implications for communication research. (SR)

Not infrequently, investigators assume that reliability for groups is greater than reliability for persons, or that the error variance for groups is less than that for persons. Using generalizability theory, it is shown that this "conventional wisdom" is not necessarily true. Examples are provided from the course-evaluation and the…

Monte Carlo studies explored the sampling characteristics of Cohen's d and three approximations to Cohen's d when used as average effect size measures in meta-analysis. Reviews of 10, 100, and 500 studies (M) were simulated, with degrees of freedom (df) varied in seven steps from 8 to 58. In a two independent groups design, samples were obtained…

This is one of a series of eight short monographs intended to aid practicing educators in planning and conducting accountability programs in schools. This booklet discusses how to determine a sampling method that is appropriate to the objectives of a particular research or evaluation effort. Short sections focus in turn on why and when to sample,…

For the purpose of obtaining data to use in test development, multiple matrix sampling plans were compared to examinee sampling plans. Data were simulated for examinees, sampled from a population with a normal distribution of ability, responding to items selected from an item universe. (Author/LMO)

A recent study (Blair and Higgins, 1980) indicated a power advantage for the Wilcoxon W Test over student's t-test when calculated from a common mixed-normal sample. Results of the present study indicate that the t-test corrected for outliers shows a superior power curve to the Wilcoxon W.

An empirical study of statistical overkill investigated the generalizability of multiple regression equations as a function of the subject/variable ratio. Data from various-sized groups of rehabilitation clients were used to develop the equations. Findings showed that equations developed on samples with less than a 10 to 1 ratio failed to…

This study developed and investigated an empirical sampling distribution of the congruence coefficient. The effects of sample size, number of variables, and population value of the congruence coefficient on the sampling distribution of the congruence coefficient were examined. Sample data were generated on the basis of the common factor model and…

A solution is proposed for analysis of variance procedures with missing cells, such as may occur when a control group is not assigned to any of the rows or columns of the various experimental groups. Mathematical models for two-way design are presented which define several variables; as well as row effect, column effect, and row and column…

Using a computer-based Monte Carlo approach to generate item responses, the results of this study indicate that, when item discrimination indices are considered, item-examinee sampling procedures having the same number of observations have different standard errors in estimating both test mean and test variance. With certain types of tests, a…

The purpose of this study was to generate descriptive statistical estimates regarding the expected proportion of occurrence of each of the PROANA 5 (Process Analysis) variables (line usage, clique group, detrimental clique group, leadership, and dominance) in small group communication. A second purpose was to determine the expected pattern of…

Linear conversions were developed relating scores on recent forms of the Graduate Record Examinations. Conversions based on specially selected subpopulations were compared with total-group conversions and evaluated. Conclusions indicated that the data clearly support the assumption of population independence for homogenoeous tests, but not quite…

Evaluations involving nonrandom assignment to treatment or control groups are vulnerable to an accidental or intentional confounding of a selection effect with the treatment effect. Two techniques, discriminant analysis and base expectancy analysis, permit separate estimation of the selection and treatment effects in the final results. (Author/CTM)