Biomedical subjects
Publications and source records attributed to F D Dunstan.
Estimation of the mean and standard deviation of a distribution using linear combinations of the order statistics of a censored sample is discussed. Existing methods are compared with the optimal estimator of this type and new approximations to the optimal estimator are proposed. Their performances in the presence of outliers are assessed by means of simulation.
One component of method comparison studies is the assessment of relative bias. Most authors use ordinary regression techniques for this purpose. The potential inadequacies in this approach are highlighted and a more generally applicable maximum likelihood technique proposed. The properties of the various methods of estimation are obtained by means of a simulation study, using a variety of different within-assay precision profiles.
In a clinical trial of an anticonvulsant drug, series of electroencephalogram readings are sometimes obtained. These may contain artefacts, that is patches of atypical values which must be identified and either removed or compensated for before a full analysis can be carried out. Methods for identifying such artefacts are discussed. These include non-parametric methods and also parametric ones combining the ideas of autoregressive modelling and of influence in regression. These methods are described and illustrated on typical data sets.