The choice of the sample is based on the rule that the statistical units get into the statistical survey randomly (not by probabilistic drawing), because they found themselves at the right time in the place where the research was carried out. This technique is widely used in surveys of consumers who are accidentally asked in shops or encountered on the street. A characteristic feature (and at the same time a disadvantage) of this technique is the fact that only an undefined part of the statistical population can be included in the survey. This fact significantly limits the possibility of generalizing later results on the entire population. The popularity of this technique is therefore determined by speed, low cost, easy access to statistical units. This technique can be used in pilot studies, but does not ensure the representativeness of the sample (representative sample).

• Non random sampling

• Statistical unit
• Representative sample