It is shown that Bayesian algorithms are computationally simpler in frequency formats than in the probability formats used in previous research. Analysis of several thousand solutions to Bayesian problems showed that when information was presented in frequency formats, statistically naive participants derived up to 50% of inferences by Bayesian…

We focus on the problem of ignoring statistical independence. A binomial experiment is used to determine whether judges could match, based on looks alone, dogs to their owners. The experimental design introduces dependencies such that the probability of a given judge correctly matching a dog and an owner changes from trial to trial. We show how…

It is well known that the two-sample Student t test fails to maintain its significance level when the variances of treatment groups are unequal, and, at the same time, sample sizes are unequal. However, introductory textbooks in psychology and education often maintain that the test is robust to variance heterogeneity when sample sizes are equal.…

In this paper, we consider some combinatorial and statistical aspects of the popular "Powerball" lottery game. It is not difficult for students in an introductory statistics course to compute the probabilities of winning various prizes, including the "jackpot" in the Powerball game. Assuming a unique jackpot winner, it is not difficult to find the…

This quantitative research study used logistical regression and ordinary least squares to examine factors that contribute to the narrowing of the achievement gap at an urban high school in the Midwest. The study analyzed the relationship between five independent variables related to participation in co curricular activities, demographic…

Correlation-based approaches to causal analysis contain too much irrelevant information that masks and modulates the true nature of causal processes in the world. Both causal modeling and path analysis/structural equations give the wrong answers for certain conceptions of causation, given certain assumptions about the "error" variables.…

Methods drawn from four logical theories associated with studies of inductive processes are applied to the assessment and evaluation of experimental episode construct validity. It is shown that this application provides for estimates of episode informativeness with respect to the person examined in terms of the construct and to the construct…

Three procedures, alpha, image, and uniqueness rescaling, were applied to a joint occurrence probability matrix. That matrix was the basis of a well-known latent class structure. The values of the recurring subscript elements were varied as follows: Case 1 - The known elements were input; Case 2 - The upper bounds to the recurring subscript…

The problem of test bias has been a growing concern in recent years. Of the several available methods for determining test bias, probably the most effective means involves collecting criterion information. This data collection process often provides a considerable barrier to the researcher, especially for the small test user and for someone who…

Models proposed by Cleary, Thorndike, Cole, Einhorn and Bass, and Darlington for analyzing bias in the use of tests in a selection strategy are surveyed. Six additional models for test bias are also introduced. The purpose is to describe, compare, contrast, and evaluate these models while, at the same time, extracting such useful ideas as may be…

Kaminsky and Nelson's method for estimating the times of future "success" from the times of earlier "successes" in the same sample is discussed in terms of its potential applications to long term psychological treatment, research, or training programs. (Author/JKS)

Describes a statistical model that can predict, throughout the fiscal year, the amount of money that will be spent on firm orders against a given fund, thereby predicting the number of orders that must still be placed to totally spend but not overspend that fund. Data tables are included. (Author/JD)

Modeling the process by which participants are selected into groups, rather than adjusting for preexisting group differences, provides the basis for several new approaches to the analysis of data from nonrandomized studies. Econometric approaches, the propensity scores approach, and the relative assignment variable approach to the modeling of…

Probability and statistics may be the horror of many college students, but if these subjects are trimmed to include only the essential symbols, they are easily within the grasp of interested middle school or even elementary school students. This book can serve as an introduction for any beginner, from gifted students who would like to broaden…