# Sample Variance, n-1 factor

People often question why is there a “n-1” term when I calculate the variance. Why not divide through by “n”. Most stats courses dismiss this question by saying, “oh, that’s because you lose a degree of freedom”. What is a degree of freedom. In the video below we ignore this notion of degree of freedom and answer where the “n-1” came from when calculating sample variance.

*Originally published at **sachinruk.github.io** on August 6, 2015.*