How to use the one proportion z-test calculator
Test whether a sample proportion differs from a hypothesised value. Enter sample proportion, hypothesised proportion, sample size in the fields above; the test statistic z, two-sided p-value are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “one proportion z test”, “is the proportion different”, “hypothesis test for proportion”, “calculate one proportion z-test”, “find test statistic z”.
Formula
Variables
- ph — Sample proportion
- p0 — Hypothesised proportion
- n — Sample size
Worked example
With sample proportion = 0.56, hypothesised proportion = 0.5, sample size = 400, the calculator gives test statistic z ≈ 2.4; two-sided p-value ≈ 1.639506 %.
Frequently asked questions
What is the one proportion z-test calculator used for?
Test whether a sample proportion differs from a hypothesised value. It helps with questions such as “one proportion z test”, “is the proportion different”, “hypothesis test for proportion”.
What is the formula for the one proportion z-test calculation?
Test statistic z = (ph-p0) / √(p0 × (1-p0) / n). Two-sided p-value (%) = 2 × (1-ncdf(abs([Test statistic z]))) × 100. Here ph is sample proportion, p0 is hypothesised proportion, n is sample size.
What inputs do I need for the one proportion z-test calculator?
You need sample proportion, hypothesised proportion, sample size. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the one proportion z-test calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the one proportion z-test result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.