Latent class models for mixed outcomes with applications in archaeometry

Latent class models are used in social sciences for classifying individuals or objects into distinct groups/classes based on responses to a set of observed indicators. The latent class model for mixed binary and metric variables (Br. J. Math. Statist. Psych. 49 (1996) 313) is extended to accommodate any type of data (including ordinal and nominal) and its use in Archaeometry for classifying archaeological findings/objects into groups is discussed. The models proposed are estimated using a full maximum like-lihood with the EM algorithm. Two data sets from archaeological findings are used to illustrate the methodology.