🎓 Statistics & Data • Hypothesis Testing
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P-Value Calculator (Hypothesis Significance)
Computes statistical p-values to determine significance against threshold alpha levels (α = 0.05, 0.01).
Significance Level (α):
Statistical Significance
P-Value from Z-Score Calculator
Convert standardized test statistics into exact two-tailed and one-tailed p-values.
Two-Tailed P-Value: P(|Z| ≥ 2.15)
p = 0.0316
Statistically Significant at α = 0.05 (p < 0.05)
Left-Tail P(Z ≤ z)0.984298.42%
Right-Tail P(Z ≥ z)0.01581.58%
What is a P-Value?
A p-value is the probability of obtaining test results at least as extreme as the observed results, assuming that the null hypothesis is true.
Formula & Step-by-Step Calculation
If p ≤ α ⟹ Reject H₀; If p > α ⟹ Fail to Reject H₀
Standard significance testing threshold.
Worked Step-by-Step Examples
Example 1
A test yields z = 2.15. Find two-tailed p-value.
Solution: p = 0.0316 (Statistically Significant at α = 0.05)
• 2 × (1 - NormalCDF(2.15)) = 2 × 0.0158 = 0.0316
Common Real-World & Academic Use Cases
- ✓ Evaluating medical clinical trial efficacy
- ✓ A/B testing conversion rate uplifts
- ✓ Scientific publication peer-review standards
How to Use the P-Value Calculator (Hypothesis Significance)
1
Select Test Type
Choose Z-Test, T-Test, or Chi-Square.
2
Enter Test Statistic
Input computed test value.
3
Read P-Value
Compare against α = 0.05 threshold.
Frequently Asked Questions
Q: Does a small p-value prove the alternative hypothesis?
No, it only provides statistical evidence against the null hypothesis.