Investigates student interpretation of research by asking samples of undergraduates, graduates, and faculty questions concerning the implications of random sampling and random assignment. Finds that random sampling is understood while the role of random assignment in interpretation of results is misunderstood. Concludes there is a need for…

Studies binomial, negative binomial, and gamma regression models and gives a detailed description of inference procedures based on them. The process of model fitting and evaluation is illustrated by examples referring to the determination of endpoints in acute and chronic toxicity tests. (17 references) (Author/MDH)

Makes the case that science is best served when researchers focus on the size of effects and their practical significance. Advocates the use of confidence intervals for deciding whether chance or sampling variability is an unlikely explanation for an observed effect. Calls for more emphasis on effect sizes in the next edition of the American…

Comparison of 88 business students who completed experiential projects involving data collection and inferential analysis with 125 who received lectures only indicated that the active learning method resulted in better understanding of statistics through the application of theory to real-life situations. (SK)

Investigates significance tests as a tool for helping to identify real effects in the face of random variation. Speculates that equivalence tests improve the logic of significance testing when demonstrating similarity is important. Reverse tests can help show that failure to reject a null hypothesis does not support that hypothesis. (Contains 30…

Two methods, direct maximum likelihood (ML) and the expectation maximization (EM) algorithm, can be used to obtain ML parameter estimates for structural equation models with missing data (MD). Although the 2 methods frequently produce identical parameter estimates, it may be easier to satisfy missing at random assumptions using EM. However, no…

Wider use in psychology of confidence intervals (CIs), especially as error bars in figures, is a desirable development. However, psychologists seldom use CIs and may not understand them well. The authors discuss the interpretation of figures with error bars and analyze the relationship between CIs and statistical significance testing. They propose…

In this article, the authors (a) illustrate how displaying disattenuated correlation coefficients alongside their unadjusted counterparts will allow researchers to assess the impact of unreliability on bivariate relationships and (b) demonstrate how a proposed new "what if reliability" analysis can complement null hypothesis significance…

While technology has become an integral part of introductory statistics courses, the programs typically employed are professional packages designed primarily for data analysis rather than for learning. Findings from several studies suggest that use of such software in the introductory statistics classroom may not be very effective in helping…

In many practical applications of item response theory, the parameters of overlapping subsets of test items are estimated from different samples of examinees. A linking procedure is then employed to place the resulting item parameter estimates onto a common scale. It is standard practice to ignore the uncertainty associated with the linking step…

Probability-based inference in complex networks of interdependent variables is an active topic in statistical research, spurred by such diverse applications as forecasting, pedigree analysis, troubleshooting, and medical diagnosis. This paper concerns the role of Bayesian inference networks for updating student models in intelligent tutoring…

In the process of developing a conditionally-dependent item response theory (IRT) model, the problem arose of modeling an underlying multivariate normal (MVN) response process with general correlation among the items. Without the assumption of conditional independence, for which the underlying MVN cdf takes on comparatively simple forms and can be…

An index that measures the degree of comfort a researcher has relative to statistical inference application is proposed. The index is calculated by selecting and weighting components inherent in the conduct of hypothesis tests and confidence intervals, and its values range from zero to one. To organize the components of the index, inference…

A study assessed the level of workers' knowledge of their pension plan's provisions related to early and normal retirement. The data used were from the 1983 Survey of Consumer Finances. The survey, which was based on a nationwide sample of more than 3,800 households and more than 1,000 public and private pension plans that covered them, asked the…

Variance stabilizing transformations yield statistics whose standard errors are only influenced by the number of observations on which they are based. A solution that can be extended to inference on all of these parameters is presented and illustrated via three examples. (TJH)