abstract: Designing studies that use latent growth modeling to investigate change over time calls for optimal approaches for conducting power analysis for a priori determination of required sample size. This investigation (1) studied the impacts of variations in specified parameters, design features, and model misspecification in simulation-based power analyses and (2) compared power estimates across three common power analysis techniques: the Monte Carlo method; the Satorra-Saris method; and the method developed by MacCallum, Browne, and Cai (MBC). Choice of sample size, effect size, and slope variance parameters markedly influenced power estimates; however, level-1 error variance and number of repeated measures (3 vs. 6) when study length was held constant had little impact on resulting power. Under some conditions, having a moderate versus small effect size or using a sample size of 800 versus 200 increased power by approximately .40, and a slope variance of 10 versus 20 increased power by up to .24. Decreasing error variance from 100 to 50, however, increased power by no more than .09 and increasing measurement occasions from 3 to 6 increased power by no more than .04. Misspecification in level-1 error structure had little influence on power, whereas misspecifying the form of the growth model as linear rather than quadratic dramatically reduced power for detecting differences in slopes. Additionally, power estimates based on the Monte Carlo and Satorra-Saris techniques never differed by more than .03, even with small sample sizes, whereas power estimates for the MBC technique appeared quite discrepant from the other two techniques. Results suggest the choice between using the Satorra-Saris or Monte Carlo technique in a priori power analyses for slope differences in latent growth models is a matter of preference, although features such as missing data can only be considered within the Monte Carlo approach. Further, researchers conducting power analyses for slope differences in latent growth models should pay greatest attention to estimating slope difference, slope variance, and sample size. Arguments are also made for examining model-implied covariance matrices based on estimated parameters and graphic depictions of slope variance to help ensure parameter estimates are reasonable in a priori power analysis. / Dissertation/Thesis / Ph.D. Educational Psychology 2011

Submitted by Joana Azevedo (joanad@id.uff.br) on 2017-11-10T14:10:23Z No. of bitstreams: 1 Dissert Patricia Morais Mattar.pdf: 3468132 bytes, checksum: df0bd167f46f819a4711603f5f18f0ba (MD5) / Approved for entry into archive by Biblioteca da Escola de Engenharia (bee@ndc.uff.br) on 2017-11-16T13:51:42Z (GMT) No. of bitstreams: 1 Dissert Patricia Morais Mattar.pdf: 3468132 bytes, checksum: df0bd167f46f819a4711603f5f18f0ba (MD5) / Made available in DSpace on 2017-11-16T13:51:42Z (GMT). No. of bitstreams: 1 Dissert Patricia Morais Mattar.pdf: 3468132 bytes, checksum: df0bd167f46f819a4711603f5f18f0ba (MD5) Previous issue date: 2017-08-28 / As substâncias radioativas têm muitas aplicações benéficas, que vão desde a geração de energia até usos em medicina, indústria e agricultura. Via de regra, elas são produzidas em locais diferentes de onde são utilizadas, precisando ser transportadas. Para que o transporte ocorra da forma segura e eficiente, devem ser atendidas normas nacionais e internacionais. Esta pesquisa objetiva avaliar os processos de análise de segurança do transporte de material radioativo realizados pelo órgão regulador no Brasil, do ponto de vista de sua conformidade com as normas da Agência Internacional de Energia Atômica (AIEA). A metodologia de autoavaliação denominada SARIS, desenvolvida pela AIEA, foi utilizada. As seguintes etapas foram desenvolvidas: avaliação do Diagnóstico e Mapeamento de Processos; respostas ao Conjunto de Questões do SARIS e questões complementares; análise SWOT; entrevistas com stakeholders e avaliação de uma missão TranSAS realizada pela AIEA em 2002. Considerando apenas as questões do SARIS, os processos estão 100% aderentes. O aprofundamento da pesquisa, entretanto, levou à elaboração de vinte e duas propostas de melhoria, além da identificação de nove boas práticas. Os resultados demonstraram que os processos de análise de segurança no transporte de material radioativo estão sendo realizados de forma estruturada, segura e confiável, mas também que há muita oportunidade de melhoria. A formulação de um plano de ação, a partir das propostas apresentadas, pode trazer ao órgão regulador muitos benefícios. Este seria um importante passo para a convocação de uma avaliação externa, proporcionando maior confiabilidade e transparência aos processos do órgão regulador. / Radioactive substances have many beneficial applications, ranging from power generation to uses in medicine, industry and agriculture. As a rule, they are produced in different places from where they are used, needing to be transported. In order for transport to take place safely and efficiently, national and international standards must be complied with. This research aims to assess the safety analysis processes for the transport of radioactive material carried out by the regulatory body in Brazil, from the point of view of their compliance with the International Atomic Energy Agency (IAEA) standards. The self-assessment methodology named SARIS, developed by the AIEA, was used. The following steps were carried out: evaluation of the Diagnosis and Processes Mapping; responses to the SARIS Question Set and complementary questions; SWOT analysis; interviews with stakeholders and evaluation of a TranSAS mission conducted by the IAEA in 2002. Considering only SARIS questions, processes are 100% adherent. The deepening of the research, however, led to the development of twenty-two improvement proposals and the identification of nine good practices. The results showed that the safety analysis processes of the transport of radioactive material are being carried out in a structured, safe and reliable way but also that there is much opportunity for improvement. The formulation of an action plan, based on the presented proposals, can bring to the regulatory body many benefits. This would be an important step towards convening an external evaluation, providing greater reliability and transparency to the regulatory body´s processes.