Why Dividing By N Underestimates the Variance

This is the follow up video to: Statistics Fundamentals: The Mean, Variance and Standard Deviation https://youtu.be/SzZ6GpcfoQY In it, we show exactly why, when we estimate the variance, dividing by 'n' underestimates the value we are interested in. It also describes why we square each term instead of taking the absolute value. The visuals used in this StatQuest make it easy to remember why we should divide by n-1, and this will save us from falling into a very common pitfall. For a complete index of all the StatQuest videos, check out: https://statquest.org/video-index/ If you'd like to support StatQuest, please consider... Patreon: https://www.patreon.com/statquest ...or... YouTube Membership: https://www.youtube.com/channel/UCtYLUTtgS3k1Fg4y5tAhLbw/join ...buying one of my books, a study guide, a t-shirt or hoodie, or a song from the StatQuest store... https://statquest.org/statquest-store/ ...or just donating to StatQuest! https://www.paypal.me/statquest Lastly, if you want to keep up with me as I research and create new StatQuests, follow me on twitter: https://twitter.com/joshuastarmer Corrections: 2:41 For just a brief moment, the estimated mean is replaced with the population mean. It should be the estimated mean the whole time. 3:23 I should have said "To understand why dividing by n underestimates the variation around the population mean". 3:40 The estimated mean was switched with the population mean. #statquest #variance