Consulta: subjectFacets:"Study design"
Registros recuperados: 2
Data/hora: 11/06/2024 04:42:31

Sample size calculations for main effects and interactions in case–control studies using Stata's nchi2 and npnchi2 functions
Provedor de dados: Research in Agricultural & Applied Economics (AgEcon Searh)
Autores: Saunders,   Catherine L.; Bishop,   D. Timothy; Barrett,   Jennifer H.
The non-central chi-squared distribution can be used to calculate power for tests detecting departure from a null hypothesis. Required sample size can also be calculated because it is proportional to the non-centrality parameter for the distribution. We demonstrate how these calculations can be carried out in Stata using the example of calculating power and sample size for case–control studies of gene–gene and gene–environment interactions. Do-files are available for these calculations.
Tipo: Journal Article
Palavras-chave: Gene–environment interaction; Gene–gene interaction; Power; Sample size; Study design; Non-central chi^2; Research Methods/ Statistical Methods.
Ano: 2003
URL: http://purl.umn.edu/116031

Conservation of Forest Biodiversity: how sample size affects the estimation of genetic parameters
Provedor de dados: Anais da Academia Brasileira de Ciências
Autores: Costa,Leonardo S. da; Corneleo,Nathana S.; Stefenon,Valdir M.
Efficient designs are crucial for population genetic studies on forest species. In this study we employed individual based simulations aiming to evaluate what fraction of a population should be sampled to obtain confident estimations of allelic richness and of inbreeding coefficient in population genetic surveys. The simulations suggest that at least 10% of the total population has to be sampled to ensure reliable estimations of allelic richness and inbreeding coefficient. This approach will allow the confidence of the genetic parameters estimations of a larger number of populations, based on a minimal sample within each one.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Sampling strategy; Study design; Allelic richness; Inbreeding coefficient.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652015000201095