The Sample Variance: Why Divide by n-1? @jbstatistics

Uploaded January 2014 | Updated September 2026, 2 hours ago

An informal discussion of why we divide by n-1 in the sample variance formula. I give some motivation for why we should divide by something less than n, and (casually) discuss the concept of degrees of freedom (in the context of the sample variance). I have another video with a mathematical proof that dividing by n-1 results in an unbiased estimator of the population variance, available at youtu.be/D1hgiAla3KI.

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