Semiparametric analyses of cross-over data with repeated measures

A model is proposed to analyze data arising from a cross-over experiment in which measurements on a control and an exposed subject are recorded over t ime within each crossover period. The model uses locally weighted quadratic regression to control for nuisance temporal trends common to both control and exposed subjects within each period and specifies a first-order autoreg ressive process to account for dependence among measurements within each lo ngitudinal sequence. We apply the model to a motivating data set in which l aboratory animals are exposed to concentrated air particles.