Variance: Why n-1? Intuitive explanation of concept and proof (Bessel‘s correction)

You might have learned that in some instances you don't divide by n when you calculate the empirical variance of your data but by n-1. This is known as Bessel's correction. In this video, I will explain when to use it, why we need a correction in the first place, and why this correction happens to be this weird n-1 thing you all know and wonder about. 0:00 - Intro 1:33 - What is variance? 4:28 - When to use the correction and what happens if you don't 9:20 - Explanation of bias involving sample mean 17:03 - Proof why n-1 eliminates bias involving sample mean 21:56 - Explanation and proof using pairwise differences 28:42 - Summary If you want to read more about the topic: https://en.wikipedia.org/wiki/Bessel'... https://aaronjfisher.github.io/why-di... https://stats.stackexchange.com/quest... https://stats.stackexchange.com/quest... https://www.quora.com/If-we-used-the-...