Tuesday, September 17, 2013

APR Tuesday Tip: Probability Samples

Front: Probability Sample

Back: A scientific sample drawn in such a way that the probability of being chosen is equal or is known. A random sample is a good example.

With random samples, I find people struggle not with providing the definition, but with really understanding it. Random samples can be hard to create. If you stop every third person to walk through your door, that is not a random sample. Those people are preselected by entering that building on that day.

You have to think about the total population that interests you. Do every single one of them have the same chance to participate? 

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