Result updated. Sample standard deviation: 3.41565.
Standard deviation result
Main result from the values entered.
Sample standard deviation
For 4 values, the sample standard deviation is 3.41565 and the population standard deviation is 2.95804.
Count
4
Mean
8.5
Population SD
2.95804
Sample variance
11.666667
Population variance
8.75
Range
4 to 12
Show calculation method
Commas, spaces and line breaks are accepted.
How this standard deviation calculator works
The calculator parses your number list, finds the mean, then measures the squared distance from each value to that mean. It shows both sample and population standard deviation.
Sample vs population standard deviation
Population standard deviation divides by the number of values. Sample standard deviation divides by one fewer than the number of values, so it needs at least two numbers.
What this calculator does not include
This is a compact summary calculator. It does not run hypothesis tests, create charts, clean spreadsheets or act as a full statistics package.
Key terms and assumptionsShort notes about sample and population calculations, variance, mean and pasted number lists.
- Sample standard deviation
- Sample standard deviation divides squared deviations by n - 1, so it needs at least two values.
- Population standard deviation
- Population standard deviation divides squared deviations by n.
- Variance
- Variance is the average squared distance from the mean. Standard deviation is the square root of variance.
- Input parsing
- Commas, spaces and line breaks can separate numbers. Invalid tokens are flagged.
- Summary only
- This calculator provides compact summary statistics, not charts or hypothesis testing.
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FAQs
What is standard deviation?
Standard deviation is a measure of how spread out values are around the mean.
What is the difference between sample and population standard deviation?
Sample standard deviation divides by n - 1 and is often used when the values are a sample. Population standard deviation divides by n.
How many numbers do I need?
Population standard deviation needs at least one value. Sample standard deviation needs at least two.
Can I paste numbers from a spreadsheet?
Yes. The calculator accepts commas, spaces and line breaks.
Does this calculate variance too?
Yes. It shows sample and population variance.
What happens to invalid entries?
Invalid entries are ignored or flagged clearly without showing technical error values.
Can I copy the summary?
Yes. Copy summary includes the main statistics.