Chi-Square Test Calculator
Statistical arithmetic aid: χ² = Σ(O−E)²/E. Goodness of fit uses matching observed and expected categories with df = k−1−p, where p is the number of parameters fitted from these counts; use p=0 only for fully specified expected proportions. 2×2 independence derives E from row and column totals and uses df=1, without Yates correction. This tool does not verify the model or sampling assumptions and provides no p-value, significance conclusion or causal judgment.
A QUICK WALKTHROUGH
How to use this tool
- Choose goodness of fit or 2×2 independence.
- Enter matching counts and fitted parameters, or the four table cells.
- Read χ², degrees of freedom and the per-cell contributions.
Chi-Square Test Calculator
Statistical arithmetic aid: χ² = Σ(O−E)²/E. Goodness of fit uses matching observed and expected categories with df = k−1−p, where p is the number of parameters fitted from these counts; use p=0 only for fully specified expected proportions. 2×2 independence derives E from row and column totals and uses df=1, without Yates correction. This tool does not verify the model or sampling assumptions and provides no p-value, significance conclusion or causal judgment.
Contribution (O−E)²/E
Separate numbers with commas, semicolons, spaces or newlines. All expected counts must be positive; no category is dropped. Results use six significant digits. Input remains in your browser.
2×2 independence
Enter four nonnegative integer counts. Every row and column total must be positive. E = row total × column total / N; df = 1. Pearson statistic without Yates correction. Some expected counts are below 5; the chi-square approximation may be unreliable.
GOOD TO KNOW
Common questions
Does it calculate a p-value?
No. It reports χ², degrees of freedom and contributions; it does not verify assumptions or give significance or causal conclusions.