Proportion Test Calculator
Easily perform a proportion hypothesis test online. Calculate test statistic, p-value, and visualize results for single proportion tests. Free and user-friendly.
The number of successful outcomes in your sample.
The total number of observations in your sample.
The proportion value stated in the null hypothesis (between 0 and 1).
Results
Test Statistic (Z):
P-Value:
Proportion Visualization
Understanding Proportion Tests
A proportion test is a type of hypothesis test used in statistics to determine if the proportion of a certain characteristic in a population is likely to be different from a hypothesized value. It's commonly used when dealing with categorical data, such as pass/fail rates, or survey responses.
For example, you might use a proportion test to check if the proportion of defective items from a manufacturing process has changed, or if the proportion of people who prefer a certain brand is significantly different from 50%. The calculator above helps you perform a one-proportion z-test, which is suitable when you have a simple random sample and want to test a hypothesis about a single population proportion.
- Null Hypothesis (H0): States that the population proportion is equal to the hypothesized proportion.
- Alternative Hypothesis (H1): States that the population proportion is different from the hypothesized proportion (two-tailed test), or greater/less than (one-tailed test). This calculator performs a two-tailed test.
- P-value: The probability of observing a test statistic as extreme as, or more extreme than, the statistic obtained from a sample if the null hypothesis is true. A small p-value (typically ≤ 0.05) suggests evidence against the null hypothesis.
This tool uses the normal approximation to the binomial distribution, which is valid when both np0 and n(1-p0) are greater than or equal to 10.