Local Influence Analysis and Cross-over Studies
2011 (English)Licentiate thesis, comprehensive summary (Other academic)
With a special reference to cross-over design models with random individual effects, the purpose of this dissertation is to develop new methodology to detect influential observations in the context of mixed linear models with explicit maximum likelihood estimators (MLEs).
Case-weighted perturbation schemes within and between subjects in mixed models are constructed. It is emphasised that perturbations should be performed under the restriction that explicit MLEs can be obtained in the perturbed model. Two influence functions, the delta-beta influence and variance-ratio influence, are tools to evaluate the influence on the estimates of mean parameters and variance parameters, respectively, with respect to the used perturbations.
The proposed approach, named the delta-beta-based local influence approach, derives the expressions of the delta-beta and variance-ratio influences for two specific cross-over designs. In both the AB|BA design (2 X 2 cross-over design) and the ABBA|BAAB design, the applied influence functions turn out to have closed-form expressions of residuals from the unperturbed models. Some graphical tools are also presented.
Place, publisher, year, edition, pages
Stockholm: Department of Statistics, Stockholm University , 2011. , 22 p.
Delta-beta-based local influence, Explicit maximum likelihood estimate, Influential observation, Mixed linear model, Perturbation scheme, Statistical diagnostics
Probability Theory and Statistics
Research subject Statistics
IdentifiersURN: urn:nbn:se:su:diva-84422ISBN: 978-91-633-9850-6OAI: oai:DiVA.org:su-84422DiVA: diva2:580386
2011-12-08, B705, Universitetsvägen 10 B, Stockholm, 13:00 (English)
von Rosen, Tatjanavon Rosen, Dietrich