A study was conducted to compare, with simulated unidimensional and two-dimensional sets, the Type I error probabilities and rejection rates obtained with two versions of the LISREL computer program, the earlier version PRELIS/LISREL 7 and the later version PRELIS2/LISREL8, a version that corrects the asymptotic covariance matrix. Unidimensional…

An electronic survey of a listserv discussion group, the Interdisciplinary Teamed Instruction (ITI) group, was conducted to learn more about the group and to explore surveying electronically. A 10-question survey was posted electronically, as were respondents' replies. Three reminders were posted over the 3-week reply period. The number of…

Structural equation modeling (SEM) attempts to remove the negative influence of measurement error and allows for investigation of relationships at the level of the underlying constructs of interest. SEM has been regarded as a "large sample" technique since its inception. Recent developments in SEM, some of which are currently available…

A methodology for estimating descriptive statistics, specifically the mean and the variance, from a sample that is not normally drawn is described. The method involves breaking the sample down into subgroups and weighting the descriptive statistics associated with each subgroup by the proportion of the population that the subgroup represents. This…

A microcomputer program that computes statistical power for analyses performed by multiple regression/correlation is described. The program features a spreadsheet-like interface, outputting the effect size and value of power corresponding to the input parameters, including predictor variables, sample size, alpha, and error type. (TJH)

Investigates the role of causal mechanism, sampling method, and sample size in causal reasoning of 216 sixth and ninth grade and college students. Subjects did not base judgments solely on covariation. Age differences were negligible when covariation was absent and striking when covariation was present. (RJC)

The impact of capitalizing on chance in item selection on the accuracy of test information functions was studied through simulation, focusing on examinee sample size in item calibration and the ratio of item bank size to test length. (SLD)

A comparison is made of the power and actual alpha levels of three tests of homogeneity for independent product-moment correlation coefficients using Monte Carlo methods while selectively studying sample size and varying the number of correlation reliabilities. How robust these are in applied work is discussed. (SLD)

Type I error rate and power for the t test, Wilcoxon-Mann-Whitney test, van der Waerden Normal Scores, and Welch-Aspin-Satterthwaite (W) test are compared for two simulated independent random samples from nonnormal distributions. Conditions under which the t test and W test are best to use are discussed. (SLD)

An outreach and linkage program for the homeless mentally ill documented successful outcomes in terms of housing but not in terms of functioning for the 163 participants. Recruitment source, client functioning cluster type, and hours of service received were predictors of the four-month residential setting. (SLD)

An empirically based paradigm for assessment and taxonomy of child, adolescent, and young adult behavioral and emotional problems is outlined, and the standardization procedures used to assess problems reported by different informants for large clinical samples are discussed. The application of the paradigm to new cases is considered. (SLD)

Formulae for estimating individual rater reliabilities from analysis of treatment effects are presented and evaluated. Monte Carlo methods illustrate the formulae. Results indicate that large sample sizes, large true treatment effects, and large differences in the actual reliabilities of raters are required for the approach to be useful. (SLD)

Application of the bootstrap method to complex psychological analysis is illustrated using a simulation experiment with two populations with small and large samples. The method provides variance estimates, allows testing of nested competing models, and gives a preliminary idea about parameter variability. (SLD)

Monte Carlo methods are used to evaluate marginal maximum likelihood estimation of item parameters and maximum likelihood estimates of theta in the two-parameter logistic model for varying test lengths, sample sizes, and assumed theta distributions. Results with 100 datasets demonstrate the methods' general precision and stability. Exceptions are…

A method is proposed for calculating the sample size needed to achieve acceptable statistical power with a given test. The minimally important difference significant (MIDS) criterion for sample size is explained and supported with recommendations for determining sample size. The MIDS criterion is computationally simple and easy to explain. (SLD)