The use of Bayesian and empirical Bayesian techniques to summarize results from parallel randomized experiments is illustrated using the results of eight such experiments from an SAT coaching study. Graphical techniques, simulation techniques, and methods for monitoring the adequacy of model specification are highlighted. (Author/JKS)

It is argued here that the choice of the appropriate method for calculating least squares analysis of variance with unequal sample sizes depends upon the question the experimenter wants to answer about the data. The different questions reflect different null hypotheses. An example is presented using two alternative methods. (Author/BW)

Issues related to the decision of the number of factors to retain in factor analyses are identified. Three widely used decision rules--the Kaiser-Guttman (eigenvalue greater than one), scree, and likelihood ratio tests--are investigated using simulated data. Recommendations for use are made. (Author/JKS)

The performance of four rules for determining the number of components (factors) to retain (Kaiser's eigenvalue greater than one, Cattell's scree, Bartlett's test, and Velicer's Map) was investigated across four systematically varied factors (sample size, number of variables, number of components, and component saturation). (Author/JKS)

Problems in testing main effects in regression analysis when there is interaction are discussed. A method by which main effects can be tested independently of the interaction is developed and compared with the hierarchical method. The method provides control of the type I error rate, but is quite conservative. (Author/JKS)

A new procedure for determining the optimal number of interpretable factors to extract from a correlation matrix is introduced and compared to more conventional procedures. The new method evaluates the magnitude of the very simple structure index of goodness of fit for factor solutions of increasing rank. (Author/CTM)

A process is described for multiple comparisons when covariates are involved in the analysis. The method can be accomplished with considerable ease whenever pairwise comparisons are involved. More complex contrasts require the use of full and restricted models of variance. (CTM)

The evaluation of competing analysis strategies based on estimator bias and variance is demonstrated using gains in standard scores and analysis of covariance procedures for quasi-experiments conforming to the fan-spread hypothesis. The findings do not lead to a uniform recommendation of either approach. (Author/JKS)

Limitations and extensions of Feldt's approach to testing the equality of Cronbach's alpha coefficients in independent and matched samples are discussed. In particular, this approach is used to test equality of intraclass correlation coefficients. (Author)

In terms of Kagan's theory of the problem-solving process, this study explores the relationship between reflection-impulsivity, hypothesis generation and testing, and evaluation of the quality of one's own solutions among children approximately 8 to 12 years old. (JMB)

When reporting results, researchers must not change predetermined significance levels. Such attempts to make results more significant are statistically inaccurate, illogical, and unethical. American Psychological Association standards for reporting significance should be more explicit. (CP)

Identifies the purpose and need for a vocational evaluation process in the correctional setting. Discusses the five steps in such a process: preliminary intake procedure, primary data gathering, hypothesis formulation phase, hypothesis testing phase, and outcome and/or follow-up. CCT)

Five methods of performing pairwise multiple comparisons in repeated measures designs were investigated. Consideration of both Type I and Type II error rates found in the simulated conditions for the five procedures suggests that a Bonferroni method utilizing a separate error term for each comparison should be employed. (Author/JKS)

Replicates the study by McGarrigle and Donaldson (1975). Considers several objections to McGarrigle and Donaldson's claim that the tasks they used did in fact test the child's ability to conserve number. A procedure free from these objections was employed in a second experiment. Discusses implications for the social psychology of the conservation…

A procedure for approximating attained significance levels of exact conditional tests is proposed. The procedure utilizes a sampling from the null distribution of tables having the same marginal frequencies as the observed tables. (Author/JKS)