Power and Sample Size Calculator
Plan sample size, power, or effect size for two proportions or two independent means.
At a glance
- Computes
- Sample size, power, or detectable effect for two proportions or two independent means.
- You supply
- Baseline, the effect you care about, alpha, power, and the allocation ratio.
- Use when
- Before a test runs, to fix the sample size the analysis will assume.
- Not for
- Deciding whether a finished test was significant. A/B Test Calculator
Density against Standardized effect
Solved value
Enter values
Sample sizes round up.
| Metric | Value |
|---|
Power against Sample size per group
n solves the named power equation, then rounds each group up
How?
How this is calculated
Proportion mode uses the two-independent-proportions z-test planning equation with pooled null variance and non-pooled alternative variance. Mean mode uses a two-sample t-test planning approximation with Cohen's d.
Formula: n solves the named power equation, then rounds each group up
Sources
- statsmodels NormalIndPower.solve_power. statsmodels. Retrieved .
- statsmodels TTestIndPower.solve_power. statsmodels. Retrieved .
- statsmodels power_proportions_2indep. statsmodels. Retrieved .
Method last reviewed