proportionZTestRequiredN
Computes the minimum sample size needed for a proportion z-test to achieve the desired power.
Given a target power and expected effectSize (Cohen's h), returns the smallest integer sample size that meets or exceeds the requested power at significance level alpha. The result is rounded up to the next whole number, with a minimum of 2.
Example:
// Per-group sample size for a two-sample proportion z-test
proportionZTestRequiredN(effectSize = 0.5, power = 0.8) // 63
// Total sample size for a one-sample proportion z-test
proportionZTestRequiredN(effectSize = 0.5, power = 0.8, twoSample = false) // 32Return
the minimum required sample size. Always at least 2.
Parameters
the expected Cohen's h effect size. Must be non-zero. The sign is ignored.
the target statistical power (probability of detecting the effect). Defaults to 0.8 (80%). Must be in (0, 1).
the significance level (Type I error rate). Defaults to 0.05 (5%). Must be in (0, 1).
the direction of the alternative hypothesis. Defaults to Alternative.TWO_SIDED.
whether this is a two-sample test. Defaults to true. When true, the returned value is the per-group sample size. When false, it is the total sample size.
See also
to compute power at a given sample size.
to find the smallest detectable effect at a given sample size.
to compute Cohen's h from two proportions.