Question
What does a p-value show?
A p-value shows how likely it would be to see a result at least this extreme if the null hypothesis were true.
Math
Use OmniCalc's p-value calculator to convert a z-score into a quick p-value for left-tailed, right-tailed, or two-sided tests.
P-value calculator
Enter a z-score and choose left-tailed, right-tailed, or two-sided testing to estimate the p-value from the normal distribution.
Why this result matters
A distinct inference-stats page that helps students move from z-scores into hypothesis-testing interpretation without drifting into the broad Statistics Calculator label. Use the tool above to enter a few clear inputs and get a practical answer you can use right away.
This p-value calculator helps students and analysts turn a z-score into a left-tailed, right-tailed, or two-sided p-value without looking up normal tables by hand. It is useful for quick hypothesis-test interpretation and significance checks.
Formula and method
The calculator converts the z-score into a normal cumulative probability, then returns the left-tailed, right-tailed, or two-sided p-value depending on the selected test direction.
Example
If the z-score is 1.96 in a two-sided test, the p-value is about 0.05.
FAQ
Short answers to the questions people often ask before or after using the tool.
Question
A p-value shows how likely it would be to see a result at least this extreme if the null hypothesis were true.
Question
One-tailed tests look in a single direction, while two-sided tests count unusual outcomes in both directions.
Question
No. A small p-value is evidence against the null hypothesis, but it does not prove a claim by itself.
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