Divide By Seven

The sample is [2, 4, 4, 4, 5, 5, 7, 9] and its mean is 5. Compute the sample variance (Bessel's correction, ddof=1) and the population variance (ddof=0).

Sample variance $4$ and standard deviation $16$ , since the standard deviation is the square of the variance.

Sample variance $\tfrac{32}{7} \approx 4.571$ , population variance $4$

Sample variance $4$ , population variance $\tfrac{32}{7} \approx 4.571$

Both equal $4$ . The divisor only matters asymptotically, and $n = 8$ is large enough that the difference is negligible.