There is a common misbelief that a greater sample is better and allows you to generalise your results. This is only partially true. A larger sample has opportunities, as the p-value (significance) becomes better (or smaller) with a larger sample, (this is the reason that there is a significant correlation of the stork population and babies). However, this does allow you per se to generalise your research results. In this session, we will talk about criteria for sample construction and about pitfalls.