INT 9600518 Sen This U.S-Czech mathematics project between Dr. Pranab Sen of the University of North Carolina, Chapel Hill, and Dr. Jana Jurechova of Charles University, Prague, will examine higher-order asymptotic properties of robust statistical procedures in the linear model and in more sophisticated contexts, such as models for longitudinal data. The researchers intend to build upon their experience in nonparametric methods and asymptotic theory to refine procedures for several related areas: 1) k-step M-estimation in linear models; 2) second order robust estimation of regression parameters; 3) relations between r-estimators and regression rank scores estimators; and 4)second order representations for statistical functionals. Results are expected to lead to choices of estimators based on computational complexities that will be useful in situations when samples are of moderate size. The researchers expect to apply their findings in the development of new statistical procedures with special emphasis on tests of hypotheses and on non-standard models that arise in biomedical and environmental applications. This project is statistics and probability fulfills the program objective of advancing scientific knowledge by enabling experts in the Unites States and Eastern Europe to combine complementary talents and share research resources in areas of strong mutual interest and competence. ??
