A chi-square test calculator analyzes categorical data to determine if there's a significant association between variables. It compares observed frequencies with expected frequencies under the null hypothesis, helping researchers validate or reject hypotheses in fields like social sciences, marketing, and biology.
Formula
χ² = Σ[(O - E)² / E], where O = Observed value, E = Expected value.
Calculator
Observed
Expected
Development Process
This calculator was built using HTML for structure, CSS for styling, and JavaScript for functionality. The UI includes dynamic table rows for data input. The chi-square formula is implemented in JavaScript, with results dynamically displayed. Testing ensured accuracy in statistical computations.
FAQs
What is a chi-square test calculator used for?
A chi-square test calculator determines if there's a significant association between categorical variables by comparing observed and expected frequencies. It's widely used in research for hypothesis testing.
Can I use this calculator for small sample sizes?
For small samples (n < 5 in any cell), use Fisher's Exact Test instead. Chi-square tests require sufficient expected frequencies for accuracy.
What data do I need for a chi-square test?
You need observed counts and expected counts (theoretical frequencies) arranged in a contingency table. Both must be categorical, not numerical.
How do I interpret the p-value?
A p-value < 0.05 typically indicates statistical significance, suggesting the observed data deviates significantly from the expected distribution.
What are degrees of freedom in chi-square tests?
Degrees of freedom = (rows - 1) * (columns - 1). It reflects the number of independent values in the data that can vary.
Can I use percentages in chi-square tests?
No. Use raw counts, not percentages or ratios. The test relies on frequency data.
What if my expected values are zero?
Zero expected values invalidate the test. Ensure all expected frequencies are at least 1, and preferably ≥5 for accuracy.
Is chi-square test only for 2x2 tables?
No. It works for any m x n contingency table, but larger tables require more data to maintain valid expected frequencies.
How accurate is this calculator?
Results are precise for valid inputs. However, always cross-check with statistical software for critical research.
What's the difference between chi-square and t-test?
Chi-square tests categorical data independence, while t-tests compare means of numerical data between groups.
