School of Mathematical Sciences Queen Mary, University of London SUMMER 2001 STATISTICS SEMINAR: DESIGN OF EXPERIMENTS All are welcome The talks are held at 16.30, all in the Mathematics Seminar Room (103) on Level 1 of the Mathematics Building, Queen Mary, University of London. Tea and coffee are available in the Mathematics Common Room (102) from 15.00. The nearest underground station is Stepney Green. Turn left at the exit and walk 400 yards. ________________________________________________________________________ DATE SPEAKER TITLE ------------------------------------------------------------------------ 17 May 2001 Carola Deppe Crossover Designs for De Montfort University Descriptive Analysis in Sensory Leicester Evaluation 24 May 2001 Robert Mee Efficient Two-Level Designs for University of Tennessee Estimating Main Effects and Two-Factor Interactions 31 May 2001 Polly Martin Screening Large Numbers University of Reading of Ingredients in the Development of Agrochemical Formulations 7 June 2001 Martina Vandebroek The Design of Blocked and Peter Goos Split-Plot Experiments Katholieke Universiteit Leuven ----------------------------------------------------------------------- For more information ask: Barbara Bogacka School of Mathematical Sciences Queen Mary, University of London Mile End Road London E1 4NS Tel: 020 7882 5497 e-mail: [log in to unmask] --------------------------------------------- The seminar information is kept on: http://www.maths.qmw.ac.uk/~rab/seminars.html ______________________________________________________________________ A B S T R A C T S ______________________________________________________________________ Carola Deppe "Crossover Designs for Descriptive Analysis in Sensory Evaluation" One of the key aims of sensory analysis is to provide methods for the objective assessment and comparison of product properties, based upon responses derived from a panel of trained assessors. In the sensory context, the choice of the statistical design for such studies takes on additional significance in attempting to cope with the inherent limitations of human response data. These limitations are especially evident when large numbers of products need to be compared in a given study, as is frequently the case, particularly within industry. In this talk I will describe a three-step procedure for creating crossover designs for multi-session experiments that have an additional constraint on the number of products that can be prepared for a single session. ---------------------------------------------------------------------- Robert Mee "Efficient Two-Level Designs for Estimating Main Effects and Two-Factor Interactions" For seven or more factors, orthogonal resolution V designs require 2-4 times as many runs as there are main effects and two-factor interactions to estimate. By forfeiting orthogonality, it is possible to substantially reduce the size of the design for estimating these linear and bilinear coefficients. I will survey the literature on irregular resolution V designs and then propose a class of designs that are fully efficient for main effects. All bilinear coefficients can be estimated from these new designs, though not with full precision. ------------------------------------------------------------------------ Polly Martin "Screening Large Numbers of Ingredients in the Development of Agrochemical Formulations" The development of an agrochemical formulation generally involved experimentation to optimise the efficacy and physical properties of the formulation. In some cases it is desirable to test a large number of potential ingredients in order to obtain the best subset for inclusion in the final product. When screening a large number of ingredients it can be useful to know, not only the effect of each individual component on the measured response, but also if an improved response can be obtained when two or more components are combined. Here a method is suggested for designing experiments to screen large numbers of components and a practical example illustrates the use of such designs. ------------------------------------------------------------------------- Martina Vandebroek and Peter Goos "The Design of Blocked and Split-Plot Experiments" Although blocked and split-plot experiments are extremely popular in practice, their optimal design has not received much attention in the literature. In the presentation, we will describe the differences and the similarities between blocked and split-plot experiments and propose a method to compute the best possible tailor-made design in a particular experimental situation. Examples will illustrate the computational results, the most striking of which is that split-plot designs are sometimes more efficient than completely randomized designs. --------------------------------------------------------------------------