Chi-Square Test Calculator
Perform a chi-square goodness-of-fit test by entering observed and expected frequencies for up to 4 categories. Get the test statistic, degrees of freedom, and approximate p-value.
The chi-square test measures how well observed data matches expected data.
Formula
χ² = Σ (Oᵢ - Eᵢ)² / Eᵢ
Where Oᵢ = observed frequency and Eᵢ = expected frequency for each category.
Degrees of freedom = number of categories - 1
A larger χ² value indicates a greater discrepancy between observed and expected. Compare the p-value to your significance level (typically 0.05) to determine statistical significance.