Sample size required to test proportion

Use this calculator to find the minimum sample size required to test hypothesis about population proportion $p$.

The minimum sample size required to test the population proportion is

$$ n =\bigg(\frac{Z_{1-\alpha/2}+Z_{1-\beta}}{ES}\bigg)^2 $$

where

  • $\alpha$ is the selected level of significance,
  • $1-\beta$ is the selected power,
  • $ES$ is the effect size.

The $ES$ is defined as $$ ES=\frac{|p_1-p_0|}{\sqrt{p_0*(1-p_0)}} $$

where

  • $p_0$ is the proportion under $H_0$ and
  • $p_1$ is the proportion under $H_1$.

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