Accounts of leadership in relation to ethics can and do go wrong in several ways that may lead us too quickly into thinking there is a tighter relationship between ethics and leadership than we have reason to believe. Firstly, these accounts can be misled by the centrality of values talk in...

Variance function estimation in multivariate nonparametric regression is considered and the minimax rate of convergence is established in the iid Gaussian case. Our work uses the approach that generalizes the one used in [A. Munk, Bissantz, T. Wagner, G. Freitag, On difference based variance...

In this article, we propose a test for the additivity of a nonlinear conditionally heteroscedastic autoregressive model. The test is based on the unequal variance unbalanced design ANOVA scheme. An asymptotic distribution of the test statistic is derived and the test performance in finite...

We are interested in modelling the time series process yt=[sigma](xt)[epsilon]t, where [epsilon]t=[phi]0[epsilon]t-1+vt. This model is of interest as it provides a plausible linkage between risk and expected return of financial assets. Further, the model can serve as a vehicle for testing the...