Sample vs Population Standard Deviation Explained
Why the denominator switches between n and n − 1
Free Calculator Hub Editorial Team
7 min read
Sample vs Population Standard Deviation Explained
Population formulas divide by n because you truly have every member. Sample formulas divide by n−1 to reduce bias when estimating the population spread from a subset.
When to use each
- Entire class scores → population
- Random survey of voters → sample
- Same numbers, different denominators → different SD