Pooled Variance Calculator
Compute pooled variance sp² from two groups' SD and sample sizes.
Input Data
Input Group1 SD s₁.
Input Group1 n₁.
Input Group2 SD s₂.
Input Group2 n₂.
Results
7.392857
sp² = ((n₁−1)s₁² + (n₂−1)s₂²) / (n₁+n₂−2).
At a glance:Pooled Variance Calculator: enter parameters to compute results; complements related calculators.
Formula
sp² = ((n₁−1)s₁² + (n₂−1)s₂²) / (n₁+n₂−2).
How to Use
- Enter each group's SD and sample size.
- It returns pooled variance sp².
Case Studies
s₁=2,n₁=10,s₂=3,n₂=20 → sp²≈7.3929
sp² = (9·4 + 19·9)/28 = 207/28 ≈ 7.3929.
FAQ
When to use pooled variance?
Use it when assuming equal variances across groups to estimate a common variance.
Related Tools
References
Content review: Calculatorism Science Team. Formula and numeric tests verified; results for reference only.