Translate: Another decision which has to be made concerns the sampling plan. A sample is a segment of the population selected to represent the population as a whole. There are three variables here: firstly the sample unit, i.e. who is to be sampled. Secondly the sample size, i.e. how many should be surveyed? Thirdly the sampling procedure, i.e. how should the people be chosen: at random, at convenience, on the basis of prejudgement?