The problems addressed, and solutions devised, by educational ethnographers in selection of and sampling from phenomena for internal representativeness external comparison are examined. The process of sampling is designated as a specialized form of the more general process of focusing and choosing in research, which is called selection. Common…

This report documents a methodological study conducted for the National Science Foundation to investigate the effects of different media environments on relationships between local television news viewing and local knowledge. The study serves two purposes: it establishes tne reliability of data collected in an investigation by Rand of the effects…

To explore the feasibility of sample selection to predict agricultural employment, a stratified sample of 360 employers was drawn from the employers reporting employment in the Disability Insurance Program for agricultural workers in Fresno County. Month-to-month changes were examined for seven industry strata, and estimates were made by the…

Investigated empirically through post mortem item-examinee sampling was the feasibility of the jackknife as a procedure for approximating standard errors of estimate in multiple matrix sampling. The parameters estimated were the mean test score, second through fourth central moments of the test score distribution, and the variance of the item…

The power of a statistical test is, in part, a function of the reliability of the dependable variable being analyzed. The substitution of sigma square divided by the reliability coefficient for sigma is proposed. This enables the researcher to incorporate dependent variable reliability information when determining the sample size required for a…

Significant cost savings can be achieved with the use of matrix sampling in estimating population parameters from psychometric data. The statistical design is intuitively simple, using the framework of the two-way classification analysis of variance technique. For example, the mean and variance are derived from the performance of a certain grade…

The primary purpose of the present study was to investigate empirically the effect of multiple hypothesis testing on error rates in factorial ANOVA designs under a variety of controlled conditions. The per comparison, per experiment, and experimentwise error rates were investigated for three hypothesis testing procedures. The specific conditions…

Basic to many psychological investigations is the question of agreement between observers who independently categorize people. Several recent studies have proposed measures of agreement when a set of nominal scale categories have been pre-defined and imposed on both observers. This study, in contrast, developes a measure of agreement for settings…

Researchers are often in a dilemma as to whether parametric or nonparametric procedures should be cited when assumptions of the parametric methods are thought to be violated. Therefore, the Kruskal-Wallis test and the ANOVA F-test were empirically compared in terms of probability of a Type I error and power under various patterns of mean…

This paper is based on a particulate pollutant system study to delineate the deficiencies in knowledge regarding the nature and magnitude of particulate pollutant emissions from stationary sources. Presented at the 12th Conference on Methods in Air Pollution and Industrial Hygiene Studies, University of Southern California, April, 1971, it focuses…

Since the development of causal path analysis by Wright, both the standardized and unstandardized procedures in path coefficient estimates have been advocated in the related literature, but the superiority of one technique over the other has not been demonstrated empirically or mathematically. In this study, the sampling properties of both…

A rederivation of Lord's formula for estimating variance in multiple matrix sampling is presented as well as the ways Cronbach's coefficient alpha and the Spearman-Brown prophecy formula are related in this context. (Author/JKS)

Confusion about the meaning of validity in quasi-experimental research can be addressed by carefully relabeling types of validity. Internal validity can more aptly be termed "local molar causal validity." More tentatively, the "principle of proximal similarity" can be substituted for the concept of external validity. (Author)

The development of a nonparametric K-sample test for equality of slopes using Puri's generalized L statistic is presented. The test is recommended when the assumptions underlying the parametric model are violated. This procedure replaces original data with either ranks (for data with heavy tails) or normal scores (for data with light tails).…