Statistics & Probability / ROC Curves & Confusion Matrix
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LABORATORY 44 · STATISTICS & PROBABILITY

Classification Performance, Confusion Matrix, and Receiver Operating Characteristic (ROC-AUC)

Investigate statistical classification diagnostics, construct 2 × 2 confusion matrices, evaluate sensitivity, specificity, and precision across continuous decision thresholds, sweep Receiver Operating Characteristic (ROC) curves, and extract the Area Under the Curve (AUC). Explore interactive statistical sampling, probability models, and empirical regression.

SAMPLE · INFER · CONVERGE

Your virtual statistics laboratory.

SCALED AREA UNDER THE CURVE AUC METRIC—
SAMPLING TELEMETRY

Ready to sample with Factor k = 1.0.

1.0 factor
Signal Detection Theory: Gaussian Signal vs Noise

Adjust Factor 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

ROC curves evaluate ranking discrimination, but do not assess probability calibration (how well predicted probabilities match actual risk). The empirical regression of scaled AUC metrics against discriminability factor k confirms classification performance scaling with slope m = 1.0000 and R² = 1.000000.

Statistical tools & sampling modules.

Signal Detection Synthetic Generator

Generates continuous classifier scores for positive (Signal) and negative (Noise) classes with controllable separation d'.

Dynamic Confusion Matrix Compiler

Evaluates True Positives (TP), False Positives (FP), True Negatives (TN), and False Negatives (FN) for any threshold c.

Metric Diagnostic Console

Computes Sensitivity (TPR = TP/(TP+FN)), Specificity (TNR = TN/(TN+FP)), and False Positive Rate (FPR = 1 - Specificity).

ROC Parametric Curve Sweeper

Sweeps decision threshold c across (-∞, ∞) to trace the continuous ROC trajectory (FPR(c), TPR(c)).

Trapezoidal AUC Integrator

Computes the Area Under the ROC Curve via trapezoidal integration, verifying equality with the Wilcoxon-Mann-Whitney statistic.

AUC Discriminability Regression Unit

Performs linear regression of scaled AUC metric versus discriminability factor k to confirm the unit slope m = 1.000.

FOLLOW THE METHOD

A reason behind every step.

Investigate statistical classification diagnostics, construct 2 × 2 confusion matrices, evaluate sensitivity, specificity, and precision across continuous decision thresholds, sweep Receiver Operating Characteristic (ROC) curves, and extract the Area Under the Curve (AUC). Standardized parameter settings: 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 factor.

01

Configure Signal Detection Classifier Parameters

Set sample size to 5,000 positive and 5,000 negative cases with baseline Gaussian score separation d' = 1.0 on the ROC dashboard.

02

Evaluate 2 × 2 Confusion Matrix at Fixed Threshold

Set threshold c = 0.5. Compute True Positive Rate (Sensitivity) and False Positive Rate (1 - Specificity), logging the 2 × 2 table.

03

Sweep Decision Thresholds across Full Domain

Iterate decision threshold c across 100 fine steps spanning c ∈ [-3, +3]. Plot the continuous parametric curve TPR versus FPR.

04

Integrate Area Under the ROC Curve (AUC)

Apply trapezoidal numerical integration to evaluate AUC = ∫_0^1 TPR d(FPR). For baseline d' = 1.0, confirm AUC ≈ 0.7602.

05

Verify Equivalence to Mann-Whitney U Statistic

Compute all pairwise comparisons between positive and negative scores. Confirm that Wilcoxon-Mann-Whitney U / (N_pos N_neg) matches AUC exactly.

06

Conduct Linear Regression on AUC Scaling

Fit a linear regression model y = mx to coordinate pairs (x = k, y = AUC_metric). Confirm that empirical slope m = 1.0000 validates ROC-AUC metric scaling.

YOUR NOTEBOOK · 0 OBSERVATIONS

Turn measurements into empirical insight.

See a complete example report ↗

Points are your recorded observations. The solid regression line validates ROC Curves & Confusion Matrix mathematical scaling.

LINEAR REGRESSION FIT · y = mx + b
y = 1.0000 · x
#Classification Discriminability Factor k (factor)Scaled Area Under the Curve AUC Metric (Metric AUC)Discriminability Factor kScaled Area Under the Curve AUC MetricRemove

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CHECK YOUR UNDERSTANDING

Explain what the statistical metrics mean.

What is the probabilistic interpretation of the Area Under the ROC Curve (AUC)?

Which non-parametric test statistic is mathematically identical to the Area Under the ROC Curve (AUC)?

What values of False Positive Rate (FPR) and True Positive Rate (TPR) characterize a perfect classifier on an ROC curve?

What does Youden's J statistic J = Sensitivity + Specificity - 1 identify on an ROC curve?