Originally Posted by

**noetsi**
Random sampling, generalizability, really has nothing to do with statistics per se. That is why it is not part of say the Gauss Markov assumptions. All the assumptions go to is whether the method estimates correctly on a given data base. They do not address, statistics does not address generally, whether you can use a given statistic to analyze a specific sample or population from another sample.

Sampling is a distinct field from statistics and has its own entirely separate set of assumptions. People tend to assume they are the same field when they are not.