Interactive Educational Tool
Sample Size & Standard Error Explorer
Adjust the parameters below to see how mean, standard deviation, and sample size affect the standard error and confidence intervals in real-time.
Parameters
Group A
Group B
Key Formulas
SE = σ / √n
95% CI = μ ± 2×SE
UB = μ + 2×SE
LB = μ − 2×SE
95% CI = μ ± 2×SE
UB = μ + 2×SE
LB = μ − 2×SE
Visualization
Standard Error (SE)
0.80
Group A
0.60
Group B
95% Confidence Interval
A: 8.4 – 11.6
B: 10.8 – 13.2
Margin of Error (2×SE)
1.60
Group A
1.20
Group B
Key Insight
As sample size increases, standard error decreases, making the confidence interval narrower and the estimate more precise.
Data Summary Table
| Parameter | Group A | Group B |
|---|---|---|
| Mean | 10.0 | 12.0 |
| Std Dev (σ) | 4.0 | 3.0 |
| Sample Size (n) | 25 | 25 |
| Standard Error (SE) | 0.80 | 0.60 |
| 2 × SE | 1.60 | 1.20 |
| Upper Bound (UB) | 11.60 | 13.20 |
| Lower Bound (LB) | 8.40 | 10.80 |