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Standard Deviation Calculator — Sample & Population Variance with Steps
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Calculated result
Sample SD 2.1381
Variance: 4.5714 · Mean: 5 · n: 8
Sum: 40 · Sum of squared deviations: 32
Population SD: 2 · Sample SD: 2.1381
Standard error: 0.7559
Coefficient of variation: 42.7618%
Tukey outliers: none
Deviation table
| x | x − mean | (x − mean)² | z | Flag |
|---|---|---|---|---|
| 2 | -3 | 9 | -1.4031 | |
| 4 | -1 | 1 | -0.4677 | |
| 4 | -1 | 1 | -0.4677 | |
| 4 | -1 | 1 | -0.4677 | |
| 5 | 0 | 0 | 0 | |
| 5 | 0 | 0 | 0 | |
| 7 | 2 | 4 | 0.9354 | |
| 9 | 4 | 16 | 1.8708 |
Show the working
- 1. Mean = 40 ÷ 8 = 5.
- 2. For each value, calculate x − mean and square that deviation; Σ(x−mean)² = 32.
- 3. Sample variance = Σ(x−x̄)² ÷ (n−1) = 4.5714.
- 4. Standard deviation = √4.5714 = 2.1381.
Choose Sample when these observations are a subset used to estimate a larger population; choose Population when the dataset contains every observation in the population you mean to describe.
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