Nonparametric comparison of regression curves by local linear fitting

Abstract

This paper proposes a new nonparametric test for the hypothesis that the regression functions in two or more populations are the same. The test is based on local linear estimates using data-driven bandwidth selectors. The test is applicable to data with random regressors and heteroskedastic responses. Simulations indicate the test has good power.Nonparametric testing Local polynomial fitting Bias correction