What's the difference between population and sample standard deviation?

Population SD divides by N, while sample SD divides by N-1 (Bessel's correction) to account for the smaller sample size.

Why use standard deviation instead of variance?

Standard deviation is in the same units as the data, making it easier to interpret. Variance is in squared units.

Standard Deviation Formula on CalcAll — free educational content with detailed examples.

What's the difference between population and sample standard deviation?: Population SD divides by N, while sample SD divides by N-1 (Bessel's correction) to account for the smaller sample size.
Why use standard deviation instead of variance?: Standard deviation is in the same units as the data, making it easier to interpret. Variance is in squared units.