The particulate sampling system currently in use by the Bay Area Air Pollution Control District, San Francisco, California is described in this presentation for the 12th Conference on Methods in Air Pollution and Industrial Hygiene Studies, University of Southern California, April, 1971. The method represents a practical, inexpensive tool that can…

A model for multiple choice test-taking behavior is proposed which is different from those presently used for item sampling theory. A new theory is developed, which includes a new concept to facilitate comprehension of item sampling theory, a "number-known" score distribution. A major advantage of the model is that it accommodates data from…

In many circumstances it is appropriate to use the school as the unit of analysis. The variables measured on students must be aggregated to form a mean for each school. However, the means derived from the students sampled in a school will tend to fluctuate around the true mean for the school in a way determined by the within-school correlations…

The distributional characteristics of the Kaiser-Rice measure of sampling adequacy (MSA) were investigated with sample correlation matrices from multivariate normal populations where the level of correlation (LC) was systematically varied. Two additional variables were manipulated--sample size (SS) and number of variables (NV). Ten matrices were…

This paper considers estimation of parameters for a model currently being used to study the Illinois Interlibrary Loan Network (ILLINET) and presents a method for determining how much data should be collected and how it should be aggregated. Four classes of model parameters discussed: demands, probabilities of success, processing times, and…

Difficulties often encountered in conducting surveys in educational technology are described, and some guidelines are suggested for the design and implementation of a survey instrument. (RAO)

Two potentially useful tests for homogeneity of variance--the jackknife test and the Box test--are described and compared. Recommendations for the use of these techniques and computational examples of each are provided. (Author/JKS)

An empirical sampling distribution of the statistic average trace (E'E) for various orders of A matrices was developed through a Monte Carlo approach. A method is presented which can be used as a guideline in determining whether factor structures obtained from two data sets are congruent. (Author/DEP)

Measurement error in dependent variables reduces the power of statistical tests to detect mean differences of specified magnitude. Procedures for determining power and sample size that consider the reliability of the dependent variable are discussed and illustrated. Methods for estimating reliability coefficients used in these procedures are…

This article presents an improved approximation formula for the problem of correcting correlation coefficients that arise from range-restricted distributions on either or both the independent and dependent variable. (BS)

Multiple matrix sampling (MMS) as a data collection strategy was examined, and rates of response from 307 public school principals in Virginia were compared when subgroups of items were administered versus an entire instrument. MMS was demonstrated as a viable and reasonable procedure when the mail questionnaire consists of a large number of pages…

Drawing a probability sample of homeless adults in Los Angeles' Skid Row resulted in a sampling design meeting statistical criteria. The design uses data from meal centers, bed counts, and outdoor congregations; and allows unbiased estimates of prevalence of mental disorders and assessment of service needs of the homeless. (TJH)

Describes a sampling strategy which involves linked pairs of persons used to obtain bereaved respondents for a study examining loss and coping responses following a recent natural disaster. The sampling procedure appeared not to produce an obvious bias and was very beneficial in meeting the research objectives. (Author/NRB)

Presents guidelines about how to conduct a public opinion poll and discusses such specific areas as the sample, the questionnaire, the interviewers, and the poll report. (DF)