The two-tailed p-value equals: 0.1336
-4-3-2-101234z = 1.5z = 1.5xx1-pval = 0.8661-pval = 0.866Null assumption (1 - α = 0.95)Null assumption (1 - α = 0.95)pval/2 = 0.0668pval/2 = 0.0668α / 2 = 0.025α / 2 = 0.025pval/2 = 0.0668pval/2 = 0.0668α / 2 = 0.025α / 2 = 0.025-1.96z_0.0251.96z_0.9751.5xDistribution: Normal(μ:0, σ:1) - Two-TailedDensitystatskingdom.com
  
You can change the 'P-value chart' to 'Significance level chart(α)' or select 'Both'

Solution



P value calculator

The p-value calculator calculates the p-value for Z score, T score, F score and Chi-square score.
If you don't have the score you may use one of the following calculators that will compute the score and the p-value:
One sample Z-test, Two sample Z-test, One sample T-test,Two-Sample T (Welch's),Two-Sample T-test (equal), Chi-squared test, F-test and more.

How to use the p-value calculator

  1. Select the relevant distribution: Normal distribution, T distribution, Chi-square distribution, or F distribution
  2. Choose the relevant tail; the default is two tails.
  3. Enter the significance level (α); the default is 0.05.
  4. Input the score which is the statistic value.
  5. Provide the distribution's parameters.
  6. Press the 'calculate' button to get the p-value, chart, and solution.

What is p value?

The p-value is the probability of obtaining the current statistical result under the assumption that H0 is correct.
If you decide to reject the H0, the p-value represents the probability of making a mistake, specifically a type I error — rejecting a correct H0. A commonly used rule defines a significance level of 0.05. When the p-value is smaller than the significance level, you can reject the null hypothesis with a low chance of error. Another commonly used significance level is 0.01.

When is p value significant?

The p-value is significant when it is equal to or lower than the significance level (α). This indicates that the probability of the null hypothesis being correct and obtaining such a score is very low, lower than the significance level.

Why do we reject the null hypothesis when the p-value is small?

The p-value represents the probability of rejecting a correct H0. When the p-value is small, the probability of rejecting a correct H0 is small, hence the probability of making a mistake is small.

P value formula

X is the test statistic value, and you know the distribution of X.
For example X may be Z, T etc.

  • Left tailed: P-value = p(x≤X)
  • Right tailed: P-value = 1 - p(x≤X)
  • Two tailed: P-value = 2 * Min( p(x≤X), 1 - p(x≤X) )