Variability (also called spread or dispersion) can be thought of as a measure of how different scores are from one another. It’s even more accurate (and maybe even easier) to think of variability as how different scores are from one particular score. And what “score” do you think that might be? Well, instead of comparing each score to every other score in a distribution, the one score that could be used as a comparison is—that’s right—the average. So, variability becomes a measure of how much each score in a group of scores differs from the average, usually the mean. More about this in a
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