P-value Calculator
Calculate the p-value from t-test, chi-square, z-score, or F-statistic.
P-value Calculator
Calculate the p-value from t-test, chi-square, z-score, or F-statistic.
Descriptive Statistics
ℹ️ Median is the middle value of sorted data. This calculator uses population (not sample) variance.
Disclaimer
Results provided by this calculator are for informational and educational purposes only. They are based on the values you enter and standard formulas, and should not be considered financial, medical, legal, or professional advice. Always consult a qualified professional before making important decisions based on these results. Roughtools makes no warranties regarding the accuracy or completeness of these calculations for your specific situation.
Frequently Asked Questions
Pro Tips
For percentage calculations, convert the percentage to a decimal first (divide by 100) — this prevents calculation errors: 15% = 0.15, so 15% of 80 = 0.15 × 80 = 12.
When working with large numbers, use scientific notation to check your work. A calculator result that's off by a factor of 10 usually means a decimal point was misplaced.
Standard deviation close to zero means data is clustered tightly around the mean. High SD means high variability. Always report both mean and SD together for complete information.
Cross-check critical calculations with a different method or tool. For geometry, verify with the Pythagorean theorem. For statistics, verify mean with (max+min)/2 as a sanity check.
When to Use This Calculator
Quickly summarise a dataset with mean, median, and standard deviation for a data analysis project.
Verify manual calculations and understand the steps in descriptive statistics problems.
Analyse survey scores or ratings to find central tendency and spread of responses.
Get quick descriptive statistics on experimental data before running formal inferential tests.
Calculate mean and variance of sales, performance scores, or customer metrics for reporting.
About the P-value Calculator
This p-value calculator computes the probability value for statistical hypothesis testing from a z-score (normal distribution), t-statistic (t-distribution), chi-square statistic, or F-statistic, for both one-tailed and two-tailed tests. Enter your test statistic and degrees of freedom to instantly see the p-value and whether your result is statistically significant at common alpha levels (0.05, 0.01, 0.001). Built for researchers, students, and analysts interpreting statistical test results.
How to Use the P-value Calculator
- 1
Select the type of test: z-test, t-test, chi-square, or F-test.
- 2
Select tail type: one-tailed (one-sided) or two-tailed (two-sided).
- 3
Enter your test statistic (z-score, t-value, χ², or F-ratio).
- 4
For t-test, chi-square, and F-test, enter the degrees of freedom.
- 5
See the p-value and whether it is significant at α = 0.05, 0.01, and 0.001.
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