Power and Sample Size Calculator

Plan sample size, power, or effect size for two proportions or two independent means.

Outcome type
Effect type
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Solved value

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Sample sizes round up.

Planning details
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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

  1. statsmodels NormalIndPower.solve_power. statsmodels. Retrieved .
  2. statsmodels TTestIndPower.solve_power. statsmodels. Retrieved .
  3. statsmodels power_proportions_2indep. statsmodels. Retrieved .

Method last reviewed