Frequently Asked Questions
When should I use a z-test?
Use a z-test when the population standard deviation σ is known. If σ is estimated from the sample, use a t-test instead.
What's the difference between one- and two-tailed?
Two-tailed tests for any difference (≠). One-tailed tests for a specific direction (> or <). Use the one-tailed when the hypothesis is directional.
What does a small p-value mean?
Strong evidence against H₀. Specifically, the probability of seeing data this extreme by chance, if H₀ were true.
Provided by AllCalculators.io
Free online calculators for everyday. No registration required.
Estimates for informational purposes only.
Important Disclaimer: Estimates for informational purposes only.
This calculator provides estimates for informational purposes only. Results are based on assumptions and may not reflect actual outcomes. Consult qualified professionals in relevant fields before making important decisions based on these results.