Worked data set
4, 6, 8, 8, 9
The mean is 7. The calculator reports both population and sample standard deviation.
- Open the Scientific Calculator and select the Statistics tab.
- Enter values separated by commas, spaces or new lines.
- Choose Calculate statistics.
- Report population SD when the data set is the whole population; report sample SD when it represents a sample from a larger population.
Why there are two answers
Population variance divides the sum of squared deviations by n. Sample variance divides by n−1 to correct the tendency of a sample to underestimate population variability.
σ = √(Σ(x−μ)²/n) s = √(Σ(x−x̄)²/(n−1))
Check the context
The symbols and wording in the question usually indicate which standard deviation is required. Do not choose the smaller or larger number merely because it looks more reasonable.
Practice
Enter 2, 3, 5, 7, 8 and compare population SD with sample SD.
What to notice
The sample SD is larger because it divides by n−1.
Try the method now
Open the calculator in a separate tab and reproduce the worked example.
Related guides
Reviewed July 17, 2026.