Test Statistic of a Sample Proportion Calculator
Calculating the test statistic of a sample proportion is crucial in statistical inference to determine if there’s a significant difference between a sample and a population. It’s used in hypothesis testing, quality control, and market research.
- Enter your sample size.
- Enter the sample proportion (between 0 and 1).
- Select your desired confidence level.
- Click ‘Calculate’.
The test statistic (z) is calculated using the formula:
z = (p – P) / √[P(1 – P)/n]
where p is the sample proportion, P is the population proportion, and n is the sample size.
| Sample Size | Sample Proportion | Test Statistic |
|---|---|---|
| 100 | 0.5 | 1.96 |
| 500 | 0.4 | 1.15 |
- Always use the correct population proportion (P) for your test.
- Consider the sample size; larger samples provide more precise estimates.
- Interpret the results in the context of your research question.
What does the test statistic tell me?
The test statistic tells you how many standard deviations your sample proportion is from the population proportion. It helps you decide if there’s a significant difference between the two.
For more information, see the BLS guide on hypothesis testing and the UK Statistics Authority’s methodology guide.