Utilize our Power Analysis Calculator to accurately estimate the optimal sample size for your research, ensuring statistically robust results. This tool helps you avoid underpowered studies, increasing the likelihood of detecting true effects. Input your desired effect size (Cohen's d), significance level (alpha), and statistical power to get instant sample size estimates. Essential for research planning and grant applications.
Formula:
The calculator estimates the required sample size per group for a two-sample t-test, assuming equal group sizes. The formula used is based on Cohen's d effect size:
n = ⌈ ( (Zα/tails + Z1-β) / d )2 × 2 ⌉
- n = Required sample size per group (rounded up to the nearest whole number)
- Zα/tails = Z-score corresponding to the significance level (α) and number of tails
- Z1-β = Z-score corresponding to the desired statistical power (1-β)
- d = Cohen's d effect size (standardized difference between means)