ARBIMETRA LAB
Cross-tabulation
Builds a two-way table with row, column and total percentages, and an optional chi-square test.
What it does
Builds a two-way table with row, column and total percentages, and an optional chi-square test.
Use it to compare how one category is distributed across another.
Data you need
- Two categorical variables
Supported data: Categorical. Level: Beginner.
Formula and method
E = (row total × column total) / n · χ² = Σ(O−E)² / E
Rows are counted into every combination of the two variables. Percentages are then taken along rows, columns and the whole table. Expected counts come from the margins and feed an optional Pearson chi-square test.
Assumptions
- Each row of data is one independent observation
Input checks
- Up to 50 categories per variable
- Expected-count warnings are shown
How to read the result
Compare row percentages across columns to see where groups differ.
Worked example
Illustrative run on Simulated study data (teaching data). These figures are the actual output of this model on that example, and they say nothing about your own data.
- 240 observations; chi-square = 4.8282, df = 2, p = 0.0894, Cramer's V = 0.1418.
- The association is not statistically significant at the 5% level.
Limitations
- Association does not establish causation
Numerical validation
Validated 16 of 16 automated checks passed, including numerical results, invalid input, missing values, small samples, constant variables, charts and the interpretation text.
| Check | Reference | Result | Abs. error | Tolerance | Source |
|---|---|---|---|---|---|
| Pearson chi-square by hand | 6.65158371 | 6.65158371 | 0.0e+0 | 1e-11 | Independent NumPy calculation |
| Row percent | 70.58823529 | 70.58823529 | 0.0e+0 | 1e-11 | Independent NumPy calculation |
| Marginal total | 30 | 30 | 0.0e+0 | 0e+0 | Hand count |
Computed with python 3.13.2, numpy 2.2.5, scipy 1.14.1, pandas 2.3.3, statsmodels 0.14.4, scikit-learn 1.7.0, in your browser. A passing check confirms the listed comparison only. It does not make any result suitable for your data, and it is not a claim of equivalence with other statistical software.
Questions
Which percentage should I read?
Use row percentages when the row variable is the group being compared, and column percentages when the column variable is.
ARBIMETRA LAB is an educational and research tool. Results should be checked by the researcher and are not professional advice.
