ORDINARY MEETING ORGANIZED BY THE RESEARCH SECTION of the RSS. Wednesday 13 October, 5.00pm at the RSS (Tea 4.30pm) PETER McCULLAGH (University of Chicago) Invariance and factorial models Summary: The definition of a factorial model is extended to designs in which two or more factors have the same set of levels. Factorial models are first characterized by invariance under selection of levels. When applied to homologous factors, this same property identifies the statistically interesting subspaces, many of which are specified by symmetry, rotation and additivity. A Postscript version of the paper is available at http://www.amsta.leeds.ac.uk/~iand/rss/oct13.ps The meeting will take place at the Royal Statistical Society, 12 Errol Street, London EC1Y 8LX (nearest underground stations are Old Street, Moorgate and Barbican). Tel: 0171 - 638 8998 For a hard copy of the paper please contact Val Evans at the RSS ([log in to unmask]), stating your full postal address. Ian Dryden Hon Secretary, Research Section, RSS ----------------------------------------------------------------------- Research Section Web page: http://www.amsta.leeds.ac.uk/~iand/rss/ressect.html %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%