Chi-Square Goodness-of-Fit Test Calculator

Observed Data and Expected Proportions

Category Name Observed Count (O) Expected Proportion (P)

Test Results

1. Summary and Expected Counts

Total Observed Count (N) =

2. Chi-Square Test Statistic (χ²)

Calculated χ² =

Degrees of Freedom (df) =

3. Critical Values (χ²critical)

For α = 0.01 (1%): χ²critical ≈

For α = 0.05 (5%): χ²critical ≈

For α = 0.10 (10%): χ²critical ≈

Note: Critical values are approximate.

4. P-value

p =

5. Decision (at α = 0.05)

6. Conclusion (at α = 0.05)

7. Chi-Square Distribution Sketch (α = 0.05)

Actions

How to Use This Calculator

  1. Enter your categories — fill in category names and observed counts. Add or remove rows as needed.
  2. Set expected proportions — enter a value between 0–1 per category (must sum to 1), or click Set Equal Proportions.
  3. Click Calculate — get the χ² statistic, degrees of freedom, p-value, and critical values instantly.
  4. Read the conclusion — if p < 0.05, reject H₀. Your data doesn't fit the expected distribution.
Chi Square test for goodness of fit
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