Visar resultat 1 - 5 av 18 avhandlingar innehållade ordet heteroscedasticity.
Sammanfattning : Animal traits differ not only in mean, but also in variation around the mean. For instance, one sire’s daughter group may be very homogeneous, while another sire’s daughters are much more heterogeneous in performance. The difference in residual variance can partially be explained by genetic differences. LÄS MER
Sammanfattning : Heteroscedasticity (or time-dependent volatility) in economic and financial time series has been recognized for decades. Still, heteroscedasticity is surprisingly often neglected by practitioners and researchers. This may lead to inefficient procedures. LÄS MER
Sammanfattning : This thesis deals with the problem of estimating a function or one of its derivatives from a set of measurements, mainly of a bivariate or spatial nature which is so common in environmental applications. In this work particular attention has been on the lidar (light detection and ranging) application which is a versatile technique for measurement of among other things atmospheric trace gases. LÄS MER
Sammanfattning : DNA microarrays are strikingly efficient tools for analysing gene expression for large sets of genes simultaneously. The aim is often to identify genes which are differentially expressed between some studied conditions, thereby gaining insight into which cellular mechanisms are differently active between the conditions. LÄS MER
Sammanfattning : This doctoral thesis consists of four chapters all related to the field of time series econometrics. The main contribution is firstly the development of robust methods when testing for Granger causality in the presence of generalized autoregressive conditional heteroscedasticity (GARCH) and causality-in-variance (i.e. spillover) effects. LÄS MER