Confidence Interval of Mean Difference
Compute the confidence interval for the difference of two means.
Input Data
Input Group1 mean x̄₁.
Input Group2 mean x̄₂.
Input Group1 SD s₁.
Input Group1 n₁.
Input Group2 SD s₂.
Input Group2 n₂.
Input Critical z.
Results
2
1.145664
0.854336
3.145664
95% CI uses z=1.96 by default.
At a glance:Confidence Interval of Mean Difference: enter parameters to compute results; complements related calculators.
Formula
diff = x̄₁ − x̄₂.
margin = z·√(s₁²/n₁ + s₂²/n₂).
CI = [diff − margin, diff + margin].
How to Use
- Enter both groups' stats and critical z (1.96 for 95%).
- It returns the difference and its CI.
Case Studies
x̄₁=10,x̄₂=8,… → diff=2, 95% CI [0.854, 3.146]
se ≈ 0.5845, margin ≈ 1.1457.
FAQ
What if the CI excludes 0?
The difference is significant at the chosen level; the means differ.
Related Tools
References
Content review: Calculatorism Science Team. Formula and numeric tests verified; results for reference only.