Why do we divide by n-1 and not n? | shown with a simple example | variance and sd

If you like to see the mathematical proof of why we divide by n-1, have a look at this video: https://youtu.be/Bmwtyz7grqk See all my videos at https://www.tilestats.com/ In this video, we will see why we need to divide by n-1 to get an unbiased estimate of the population variance. We will use simple simulated data to understand this (no advanced math). At the end of the video, we will see that the sample standard deviation is a biased estimate.