Jeffrey N. Jonkman

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For random effects meta-regression inference, variance estimation for the parameter estimates is discussed. Because estimated weights are used for meta-regression analysis in practice, the assumed or estimated covariance matrix used in meta-regression is not strictly correct, due to possible errors in estimating the weights. Therefore, this note(More)
For random effects meta-analysis, seven different estimators of the heterogeneity variance are compared and assessed using a simulation study. The seven estimators are the variance component type estimator (VC), the method of moments estimator (MM), the maximum likelihood estimator (ML), the restricted maximum likelihood estimator (REML), the empirical(More)
The purpose of this study was to use a meta-analytic procedure to synthesize the rates of disordered gambling for college students that have been reported in the research literature. In order to identify all possible studies that met stringent inclusion criteria, Medline, PsychINFO, and SocioIndex databases were searched with the terms "gambling," and(More)
Heteroscedasticity is commonly encountered when fitting nonlinear regression models in practice. We discuss eight different variance estimation methods for nonlinear regression models with heterogeneous response variances, and present a simulation study to compare the performance of the eight methods in terms of estimating the standard errors of the fitted(More)
For bioassay data in drug discovery and development, it is often important to test for parallelism of the mean response curves for two preparations, such as a test sample and a reference sample in determining the potency of the test preparation relative to the reference standard. For assessing parallelism under a four-parameter logistic model, tests of the(More)
Translating the timing of brain developmental events across mammalian species using suitable models has provided unprecedented insights into neural development and evolution. More importantly, these models can prove to be useful abstractions and predict unknown events across species from known empirical event timing data retrieved from published literature.(More)
Background and aims The relationship between college student gambling, parenting styles, and family environments is a neglected area of gambling research. Do parenting styles indirectly influence problem gambling behaviors via family environments? Do poor family environments, characterized by high levels of conflict and low levels of cohesion, increase the(More)
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