The most common form of data for socio-economic studies comes from survey sampling. Often the designs of such surveys are complex and use stratification as a method for selecting sample units. A parametric regression model is widely employed for the analysis of such survey data. However the use...

Web-surveys are more and more widespread due to their easiness and rapidity; nevertheless, the ones for which mailing lists are not used, cannot be scientifically valued as they show serious coverage errors. In fact, how it is underlined in par.2, the web-population P(w) represents only a subset...