Sampling Methods

Probability Sampling Strategies		< back		4 of 36		next >


	Probability sampling strategies typically use a random or chance process, although there are important exceptions to this rule. Random sampling is a strategy for selecting study participants in which each and every person has an equal and independent chance of being selected. What does it mean to be independent? The researchers select each person for the study separately.
Let's say you were asked to participate in an experiment, enjoyed it, and told your friends to contact the researcher to volunteer for the study. This would be an example of non-independent sampling. We assume that friends share similar values and by recruiting your friends to be in the study, the sample might represent you and your friends but not the whole population of interest. The "equal chance" and "independent" components of random sampling are what makes us confident that the sample has a reasonable chance of representing the population.