🔬 Hypothesis Testing Calculator
Test a claim about a population mean with a one-sample z-test. Enter your sample statistics to get the z-score, p-value, and a decision at your chosen significance level.
What this hypothesis test does
This calculator runs a one-sample z-test, a standard method for checking whether a sample mean is significantly different from a claimed or hypothesized population mean, when the population standard deviation is known (or a large sample is used).
How it works
Enter your sample’s mean, the value you are testing against, the standard deviation, and the sample size. The calculator computes the z-statistic as the difference between the two means divided by the standard error, then converts that into a p-value using the standard normal distribution. Choosing a two-tailed, left-tailed, or right-tailed test changes how that p-value is calculated to match your hypothesis.
If the p-value is smaller than your chosen significance level (alpha), the result is typically considered statistically significant and the null hypothesis is rejected. This tool is for general educational and planning purposes, not a substitute for formal statistical consulting.