A process in a random sample of units derived from the study population. If, as the survey research will be a random person to answer the questionnaire. If a research document or to the document content analysis.
The process is a systematic random sample from a population study. If the survey Individuals will be randomized to respondents. If research papers It is a randomized document or its contents analyzed.
A process that is a system, in a random sample from the population of interest to study unit. If the survey A random person to answer queries. If research documents. Is random or document content were analyzed.