How it works
Under a normal model, p-values are areas under Φ. Two-tail p = 2(1−Φ(|z|)). Smaller p means stronger evidence against H₀.
p_two=2(1−Φ(|z|)) · p_left=Φ(z) · p_right=1−Φ(z)
When to use
Use this tool when you need to: try z=1.96 (two-tail p≈0.05) or invert from two-tail p=0.05 to recover z≈1.96. Optional α=0.05 for a reject decision.
How to use this tool
- Enter your values in the fields above.
- Review the formula and any mode options for your problem.
- Read the result and the step-by-step solution.
Try z=1.96 (two-tail p≈0.05) or invert from two-tail p=0.05 to recover z≈1.96. Optional α=0.05 for a reject decision.
Frequently asked questions
- What is the P-value Calculator?
- Under a normal model, p-values are areas under Φ. Two-tail p = 2(1−Φ(|z|)). Smaller p means stronger evidence against H₀.
- How do I use the P-value Calculator?
- Enter the required values, then calculate. The P-value Calculator shows results, formulas, and step-by-step work when available. No account is required.
- What formula does the P-value Calculator use?
- p_two=2(1−Φ(|z|)) · p_left=Φ(z) · p_right=1−Φ(z)
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