One-Sample Proportion Calculator
FreeCalculate the sample size needed to test a single proportion against a known or hypothesized value.
Study Parameters
Results
Required Sample Size
44
Achieved Power
80.4%
Effect Size
0.412
Method: Two-sided one-proportion z-test
Cohen's h0.412
Absolute difference0.200
- •Binary outcome
- •Normal approximation to the binomial distribution
- •Two-sided hypothesis test
Formula
n = [z_{alpha/2} * sqrt(p0*q0) + z_beta * sqrt(p1*q1)]^2 / (p1 - p0)^2
References
- Fleiss JL (1981). Statistical Methods for Rates and Proportions. Wiley.