Selecting participants

Random sampling

Systematic sampling – e.g., every 3rd person

Stratified sampling – based upon a representative subset

Samples of convenience

  • Who can you get?
  • Are they representative of the target population?

Transcript

Now, if you're selecting participants for some activity, you need to figure out how you're going to select them. So, for example, you might do a random selection, or you might systematically select every third person who comes through that door - we're going to ask them a question.  Or a stratified sampling, choosing members from representative sets of the data. Or one of the most common, of course, is samples of convenience: Who can I get to actually take my survey?  And then I have to figure out if they are actually representative of the target population or not. If they are, maybe it works.  If they're not, it may not give me any useful data.