Statistics & Probability / Chi-Squared Independence Test
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LABORATORY 30 · STATISTICS & PROBABILITY

Contingency Table Analysis, Chi-Squared Test of Independence, and Cramér's V

Construct two-way contingency tables, compute expected marginal product frequencies, perform the Chi-Squared test of independence, quantify association strength via Cramér's V, and verify the association scaling law. Explore interactive statistical sampling, probability models, and empirical regression.

SAMPLE · INFER · CONVERGE

Your virtual statistics laboratory.

SQUARED ASSOCIATION METRIC V²—
SAMPLING TELEMETRY

Ready to sample with Coupling k = 1.0.

1.0 factor
2 × 2 cross-tabulation matrix

Adjust Coupling k, then execute statistical trial.

Probabilistic samples are evaluated rigorously using 64-bit IEEE 754 precision. Residuals reflect ordinary least-squares regression across successive observations. Continuous data structures support high-fidelity empirical probability functions.

Statistical assumptions and distribution limits

The Chi-Squared test of independence measures statistical association, but cannot establish directional causation. The empirical regression of squared Cramér's V against coupling factor k confirms theoretical association scaling with slope m = 0.0400 and R² = 1.000000.

Statistical tools & sampling modules.

Cross-Tabulation Matrix Compiler

Sorts bivariate categorical observations into R × C contingency tables and computes row and column marginal sums.

Marginal Independence Evaluator

Computes expected independence frequencies E_{ij} = (R_i · C_j) / N under the null hypothesis of statistical independence.

Pearson Contingency Engine

Calculates the total independence statistic χ² = ∑∑ (O_{ij} - E_{ij})^2 / E_{ij} with (R - 1)(C - 1) degrees of freedom.

Yates Continuity Corrector

Applies Yates' continuity correction |O - E| - 0.5 to 2 × 2 tables to prevent Type I error inflation in moderate samples.

Cramér's V Effect Size Meter

Computes normalized association strength V = √[χ² / (N · min(R - 1, C - 1))] bounded strictly in [0, 1].

Contingency Association Regression Unit

Performs linear regression of squared Cramér's V versus coupling factor k to extract the slope m = 0.040.

FOLLOW THE METHOD

A reason behind every step.

Construct two-way contingency tables, compute expected marginal product frequencies, perform the Chi-Squared test of independence, quantify association strength via Cramér's V, and verify the association scaling law. Standardized parameter settings: 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 factor.

01

Initialize Cross-Tabulation Dimensions

Set contingency table dimensions to R = 2 rows and C = 2 columns with total sample size N = 1,000 on the simulation dashboard.

02

Synthesize Bivariate Categorical Data under Independence

Generate 1,000 independent pairs with marginal probabilities p_row = [0.5, 0.5] and p_col = [0.5, 0.5]. Compute expected cell counts E_{ij} = 250.

03

Evaluate Pearson Test Statistic under H_0

Compute χ² across 20,000 runs under complete independence. Confirm that empirical mean test statistic equals degrees of freedom df = (2-1)(2-1) = 1.000.

04

Introduce Controlled Bivariate Association

Inject an association coupling bias into the diagonal cells. Compute Cramér's V = √[χ² / (1000 · 1)] to quantify effect magnitude.

05

Step Association Coupling Factor Across k = 1 to 6

Increment the coupling factor across standardized settings k ∈ {1.0, 2.0, 3.0, 4.0, 5.0, 6.0}, recording the squared association metric V².

06

Conduct Linear Regression on Association Scaling

Fit a linear regression model y = mx to coordinate pairs (x = k, y = V²). Confirm that empirical slope m = 0.0400 matches theoretical quadratic coupling.

YOUR NOTEBOOK · 0 OBSERVATIONS

Turn measurements into empirical insight.

See a complete example report ↗

Points are your recorded observations. The solid regression line validates Chi-Squared Independence Test mathematical scaling.

LINEAR REGRESSION FIT · y = mx + b
y = 0.0400 · x
#Association Coupling Factor k (factor)Squared Association Metric V² (Cramér V²)Coupling Factor kSquared Association Metric V²Remove

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CHECK YOUR UNDERSTANDING

Explain what the statistical metrics mean.

What are the degrees of freedom for a Chi-Squared test of independence on a 3 × 4 contingency table?

What is the expected cell frequency E_{ij} under the null hypothesis of independence in an R × C contingency table?

Which normalized effect size metric measures categorical association strength bounded strictly between 0 and 1?

For a 2 × 2 table with cells [[a, b], [c, d]], what is the formula for the Odds Ratio (OR)?