Please watch clip to answer question.

https://www.khanacademy.org/math/ap-statistics/summarizing-quantitative-data-ap/more-standard-deviation/v/another-simulation-giving-evidence-that-n-1-gives-us-an-unbiased-estimate-of-variance

The sample variance ("sigma hat squared) is formulated as the sum of squared distances between actual value and sample mean divided by sample size minus 1. Based on the class discussion, why did statisticians decide that it is best to divide by "n-1" in the formula for sample variance?