Chi-Square Calculator
Calculate the chi-square statistic comparing observed and expected frequencies.
Calculate
Enter your values below.
Result
Chi-square (χ²)
0
Formula used
χ² = Σ ((Observed − Expected)² ÷ Expected)
Example: Observed 18,22,20,30 vs expected 22.5 each → χ² ≈ 4.62.
How to use this calculator
- Enter Observed values (comma-separated), Expected values (comma-separated).
- Press Calculate to see your result instantly.
FAQ
Frequently asked questions
What is the chi-square statistic used for?
Testing whether observed frequencies differ significantly from expected frequencies, common in goodness-of-fit tests.
Do the two lists need to match in length?
Yes, each observed value needs a corresponding expected value.
What does a higher chi-square value mean?
A bigger difference between what was observed and what was expected.
Does this tell me statistical significance directly?
It gives the statistic itself; comparing it to a chi-square critical value (based on degrees of freedom) determines significance.