免费P值计算器
根据检验统计量计算P值，判断统计显著性。
Approx. Two-Tailed P-Value
0.041889
Approx. Two-Tailed P-Value vs Z-Statistic (or test statistic)
公式
## How to Interpret P-Values ### Concept The p-value is the probability of observing a test statistic as extreme or more extreme than the computed value, assuming the null hypothesis is true. A small p-value (typically < 0.05) provides evidence against the null hypothesis. This calculator provides an approximation for the two-tailed p-value using the normal PDF. For exact values, consult a z-table or statistical software.
计算示例
A z-test yields z = 2.1. Is this significant at the 5% level?
- 01|z| = 2.1
- 02PDF at z=2.1: phi(2.1) = 0.04398
- 03Approximate two-tailed p ≈ 2 * 0.04398 / 2.1 ≈ 0.0419
- 04Since 0.0419 < 0.05, the result is statistically significant at the 5% level
- 05Since 0.0419 > 0.01, it is NOT significant at the 1% level
常见问题
What does a p-value of 0.05 mean?
If the null hypothesis is true, there is a 5% chance of getting a result this extreme or more extreme by random sampling. It does not mean there is a 5% chance the null is true.
Is a smaller p-value always better?
A smaller p-value provides stronger evidence against the null, but statistical significance does not imply practical significance. Always consider effect size alongside the p-value.
What is the difference between one-tailed and two-tailed p-values?
A two-tailed p-value tests for any difference (positive or negative) and is double the one-tailed value. One-tailed tests have more power but assume you know the direction of the effect in advance.
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