Z-Test Calculator (Hypothesis Testing)
Test a population mean using a Z-test and determine statistical significance.
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Uses the standard normal (Z) distribution. Assumes known population standard deviation.
Example
Sample mean = 52
Hypothesized mean = 50
Standard deviation = 8
Sample size = 64
Z = 2.00 → Reject H₀ at α = 0.05
Hypothesized mean = 50
Standard deviation = 8
Sample size = 64
Z = 2.00 → Reject H₀ at α = 0.05
What is a Z-test?
A Z-test is a statistical hypothesis test used to determine whether a sample mean significantly differs from a hypothesized population mean.
When should you use a Z-test?
Z-tests are appropriate when the population standard deviation is known and the sample size is sufficiently large.
Frequently Asked Questions
What does rejecting the null hypothesis mean?
It means there is enough statistical evidence to conclude that the true mean differs from the hypothesized value.
What if the population standard deviation is unknown?
In that case, a T-test should be used instead.