Advanced Z-Test Calculator
Perform statistical hypothesis testing with this advanced Z-Test calculator. Input your data, select your test type, and get detailed results with visualizations.
Test Parameters
0.05
0.01
0.05
0.1
Test Results
Enter your parameters and click “Calculate Z-Test” to see results
Z-Score
0.00
P-Value
0.0000
Test Conclusion
Result will appear here
Critical Values
±1.96
Confidence Interval
( – , – )
Distribution Visualization
About Z-Test
A Z-test is any statistical test for which the distribution of the test statistic under the null hypothesis can be approximated by a normal distribution. Z-tests test the mean of a distribution.
When to use a Z-test
- Your sample size is greater than 30. Otherwise, use a t-test.
- Data points should be independent from each other.
- Your data should be normally distributed. However, for large sample sizes (over 30) this assumption isn’t too important due to the Central Limit Theorem.
- Your data should be randomly selected from a population, where each item has an equal chance of being selected.
- Sample sizes should be equal if at all possible.
Z-test Formula
Z = (x̄ – μ) / (σ / √n)
Where:
- x̄ is the sample mean
- μ is the population mean
- σ is the population standard deviation
- n is the sample size