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Statistical Power Calculator
Estimate statistical power for a two-sample comparison of means.
chart Free Online Tool
⚡ Instant Results
📊 Clear Comparison
🔒 100% Free Tool
Power
Compare Your Options And Get Clear Answers
Estimate statistical power for a two-sample comparison of means.
Statistical Power Estimator
Enter your numbers below for an instant estimate.
0
💡 Tip: Power = Phi(d sqrt(n/2) – z).
How It Works
Key concepts behind this calculator
1
Enter Values
Fill in each field with your own numbers.
2
Calculate
Results update as you change the inputs.
3
Review
Read the breakdown and the explanation.
4
Adjust
Change values to compare scenarios.
Quick Reference Guide
Statistical Quick Guide
Typical values for reference.
| Effect d | n per group | Alpha | Power |
|---|---|---|---|
| 0.5 | 20 | 0.05 | 35.2% |
| 0.5 | 64 | 0.05 | 80.7% |
| 0.5 | 100 | 0.05 | 94.2% |
| 0.2 | 200 | 0.05 | 51.6% |
| Rule of Thumb | Check inputs | Use as a guide | Round sensibly |
Common Questions
Statistical Power Calculator FAQ
Answers to common questions about this calculator.
Normal approx.
It gives a quick estimate of statistical power from the values you enter.
No. It is a planning estimate, so check important figures with a professional or official source.
Yes. Edit any field and the result updates when you calculate.