Biomedical subjects

Joseph R Rausch

Publications and source records attributed to Joseph R Rausch.

4 recordsLinked to original sources

PubMed2006

Sample size planning for the standardized mean difference: accuracy in parameter estimation via narrow confidence intervals.

Methods for planning sample size (SS) for the standardized mean difference so that a narrow confidence interval (CI) can be obtained via the accuracy in parameter estimation (AIPE) approach are developed. One method plans SS so that the expected width of the CI is sufficiently narrow. A modification adjusts the SS so that the obtained CI is no wider than desired with some specified degree of certainty (e.g., 99% certain the 95% CI will be no wider than omega). The rationale of the AIPE approach to SS planning is given, as is a discussion of the analytic approach to CI formation for the population standardized mean difference. Tables with values of necessary SS are provided. The freely available Methods for the Behavioral, Educational, and Social Sciences (K. Kelley, 2006a) R (R Development Core Team, 2006) software package easily implements the methods discussed.

Confidence Intervals↗

PubMed2006

Adaptive change in self-concept and well-being during conjugal loss in later life.

The present study examines the association between the self-concept and adaptation to conjugal loss; the primary aim was to explore whether those individuals high in self-esteem, environmental mastery, and optimism have more adaptive resources with which to ameliorate the detrimental sequelae of bereavement. Analyses were conducted on data collected from 58 widows every four months over a two-year period. One goal of the research was to explore the adequacy of the theoretically chosen operational definition of the self-concept; another goal was to analyze how changes in the level of self-concept components correlated with changes in levels of depression, health, and grief resolution as individuals adjusted to their losses. Analyses revealed that trajectories of depression and grief resolution were more highly related than health to changes in self-concept.

Adaptation, Psychological↗

PubMed2003

Obtaining power or obtaining precision. Delineating methods of sample-size planning.

Sample-size planning historically has been approached from a power analytic perspective in order to have some reasonable probability of correctly rejecting the null hypothesis. Another approach that is not as well-known is one that emphasizes accuracy in parameter estimation (AIPE). From the AIPE perspective, sample size is chosen such that the expected width of a confidence interval will be sufficiently narrow. The rationales of both approaches are delineated and two procedures are given for estimating the sample size from the AIPE perspective for a two-group mean comparison. One method yields the required sample size, such that the expected width of the computed confidence interval will be the value specified. A modification allows for a defined degree of probabilistic assurance that the width of the computed confidence interval will be no larger than specified. The authors emphasize that the correct conceptualization of sample-size planning depends on the research questions and particular goals of the study.

Analysis of Variance↗

PubMed2003

Analytic methods for questions pertaining to a randomized pretest, posttest, follow-up design.

Delineates 5 questions regarding group differences that are likely to be of interest to researchers within the framework of a randomized pretest, posttest, follow-up (PPF) design. These 5 questions are examined from a methodological perspective by comparing and discussing analysis of variance (ANOVA) and analysis of covariance (ANCOVA) methods and briefly discussing hierarchical linear modeling (HLM) for these questions. This article demonstrates that the pretest should be utilized as a covariate in the model rather than as a level of the time factor or as part of the dependent variable within the analysis of group differences. It is also demonstrated that how the posttest and the follow-up are utilized in the analysis of group differences is determined by the specific question asked by the researcher.

Analysis of Variance↗