Sampling designs and estimation procedures are considered for the spatial variogram when no information on magnitude or scale of variation of a spatial variable is available. Design-based solutions to ...

Outcome-dependent sampling designs are strategic methodologies in longitudinal research that prioritise the selection of study subjects based on observed outcomes. Rather than relying on random ...

In this paper we consider a family of sampling designs for which increasing first-order inclusion probabilities imply, in a specific sense, increasing conditional inclusion probabilities. It is proved ...