The effectiveness of four methods of handling missing data in reproducing the target sample covariance matrix and mean vector was tested using three levels of incomplete cases: 30%, 50%, and 70%. Data were selected from the National Education Longitudinal Study (NELS) database. Three levels of sample sizes (500, 1000, and 2000) were used. The…

A simulation study was conducted to obtain approximate moments of the distribution of the product of two dependent correlation coefficients. The parameters in the simulation were sample size and three population corrections. In general, the simulation results were not very satisfactory. The approximated mean, variance, and skewness were accurate…

A large sample technique attributed to L. Marascuilo, based on the multiple comparison technique of H. Scheffe, was programmed with the Statistical Analysis System (SAS), focusing on comparisons among independent binomial samples. Use of the SAS program is discussed. (SLD)

Varied the number of items and categories per item to explore the effects on estimation of item parameters in the nominal response model. Simulation results show that increasing the number of items had little effect on item parameter recovery, but increasing the number of categories increased the error variance of the parameter estimates. (SLD)

Derived an approximate test and confidence interval for coefficient alpha and used the approximate test and confidence interval to derive closed-form sample size formulas that can be used to determine the sample size needed to test coefficient alpha with desired power or to test coefficient alpha with desired precision. (SLD)

Examined 20 goodness-of-fit indexes based on the minimum fit function using a simulation under the 2-group situation. Results support the use of the delta comparative fit index, delta Gamma hat, and delta McDonald's Noncentrality Index to evaluation measurement invariance. These three approaches are independent of model complexity and sample size.…

Sees soft data, measures having substantial intrasubject variability due to errors of measurement or response inconsistency, as important measures of response in randomized clinical trials. Shows that using intensive design and slope of response on time as outcome measure maximizes sample retention and decreases within-group variability, thus…

Discusses the squared cross-validity coefficient as a measure of the predictive validity of a sample linear prediction equation. Presents sample-size tables that should result in very small discrepancies between the squared multiple correlation and the squared cross-validity correction, thus facilitating the selection of sample size for predictive…

Proposes a revised index of interrater agreement for multi-item ratings of a single target. This index is an inverse linear function of the ratio of the average obtained variance to the variance of the uniformly distributed random error. Discusses the importance of sample size for the index. (SLD)

Examined the effects of ignoring multilevel data structures in nonhierarchical covariance modeling using a Monte Carlo simulation. Results suggest that when the magnitudes of intraclass correlations are less than 0.05 and the group size is small, the consequences of ignoring the data dependence within the multilevel data structures seem to be…

Studied sample sizes for confidence intervals on the increase in the squared multiple correlation coefficient using simulation. Discusses predictors and actual coverage probability and provides sample-size guidelines for probability coverage to be near the nominal confidence interval. (SLD)

Sample size recommendations in confirmatory factor analysis (CFA) have recently shifted away from observations per variable or per parameter toward consideration of model quality. Extending research by Marsh, Hau, Balla, and Grayson (1998), simulations were conducted to determine the extent to which CFA model convergence and parameter estimation…

Measurement invariance is a necessary condition for the evaluation of factor mean differences over groups or time. This article considers the potential problems that can arise for tests of measurement invariance when the true factor-to-indicator relationship is nonlinear (quadratic) and invariant but the linear factor model is nevertheless…

All differential item functioning (DIF) methods require at least a moderate sample size for effective DIF detection. Samples that are less than 200 pose a challenge for DIF analysis. Smoothing can improve upon the estimation of the population distribution by preserving major features of an observed frequency distribution while eliminating the…

Researchers have suggested that fraternity membership is the most reliable predictor of gambling and gambling problems on campus. The purpose of this study was to determine if problematic gambling could be linked to specific aspects of fraternity membership. Though the null hypothesis (no enabling environment) failed to be rejected, descriptive…