“…However there exists a suitable resampling procedure which is specifically tailored for the testing problem (1.2) and circumvents this drawback. The consistency of this resampling scheme has been shown by Zhu (2005, §5), Delgado & González-Manteiga (2001) and Härdle et al (1998), with different testing procedures for the partial linear model hypothesis (1.2). In practical terms the resampling is implemented as follows: Conditionally on the observations {y j , x j , z j } n j=1 , fit the model according to H 0 , yielding residuals { ε j } n j=1 , and calculate the corresponding value, say T , for the test statistic.…”