Conference of the Gamma Ray Bursts, Anapolis, Brezilya, 1 - 04 Kasım 2010, cilt.1358
In these proceedings we present a systematic and statistical comparison of 26 well sampled optical/UV light curves with their X-ray counterparts. We use three statistical methods to compare their behaviour and to determine the average properties of the sample and the properties of the individual GRBs.