Statistics & Probability / Principal Component Analysis
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LABORATORY 43 · STATISTICS & PROBABILITY

Principal Component Analysis (PCA), Covariance Decomposition, and Dimensionality Reduction

Investigate multivariate dimensionality reduction, compute sample covariance matrices, execute Singular Value Decomposition (SVD) and eigendecomposition, project observations onto principal axes, and verify variance scaling. Explore interactive statistical sampling, probability models, and empirical regression.

SAMPLE · INFER · CONVERGE

Your virtual statistics laboratory.

FIRST PRINCIPAL COMPONENT EIGENVALUE Λ_1—
SAMPLING TELEMETRY

Ready to sample with Scale k = 1.0.

1.0 factor
Bivariate Gaussian with correlation r = 0.80

Adjust Scale 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

PCA is an unsupervised linear method; it cannot detect complex non-linear manifold structures (e.g., Swiss roll). The empirical regression of dominant eigenvalues against total variance scale confirms principal component scaling with slope m = 0.4000 and R² = 1.000000.

Statistical tools & sampling modules.

Multivariate Centered Data Matrix

Standardizes raw observation vectors into centered matrix X̃ = X - 1 x̄^T with zero empirical column means.

Sample Covariance Matrix Calculator

Computes sample covariance matrix S = (1/(n-1)) X̃^T X̃ across multi-attribute observations.

SVD & Eigendecomposition Engine

Computes eigenvalues λ_j and orthogonal eigenvectors v_j satisfying S v_j = λ_j v_j via QR iteration.

Scree Plot Variance Ratio Analyzer

Calculates proportion of variance explained by each principal component: PV_j = λ_j / ∑ λ_i.

Orthogonal Projection Transformer

Projects observations onto principal axes Z = X̃ V to construct uncorrelated score coordinates.

Principal Variance Regression Unit

Performs linear regression of dominant eigenvalue λ_1 versus scale factor k to extract slope m = 0.400.

FOLLOW THE METHOD

A reason behind every step.

Investigate multivariate dimensionality reduction, compute sample covariance matrices, execute Singular Value Decomposition (SVD) and eigendecomposition, project observations onto principal axes, and verify variance scaling. Standardized parameter settings: 1.0, 2.0, 3.0, 4.0, 5.0, 6.0 factor.

01

Configure Bivariate Correlated Data Structure

Set sample size n = 10,000 observations with bivariate covariance matrix Σ having correlation r = 0.80 on the PCA dashboard.

02

Center and Standardize Input Coordinates

Subtract column means to form centered matrix X̃. Verify that empirical means equal zero across all attributes.

03

Execute Eigendecomposition on Sample Covariance

Compute covariance matrix S and solve for eigenvalues (λ_1, λ_2) and orthogonal eigenvectors (v_1, v_2). Verify v_1^T v_2 = 0.

04

Measure Proportion of Variance Explained

Evaluate the scree ratio PV_1 = λ_1 / (λ_1 + λ_2). For r = 0.80 and normalized variance, verify dominant component captures 40% of baseline scale.

05

Step Total Variance Scale Across k = 1 to 6

Increment total variance scale across standardized steps k ∈ {1.0, 2.0, 3.0, 4.0, 5.0, 6.0}, recording the dominant eigenvalue λ_1.

06

Conduct Linear Regression on PCA Eigenvalue Scaling

Fit a linear regression line y = mx to coordinate pairs (x = k, y = λ_1). Confirm that empirical slope m = 0.4000 validates principal variance 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 Principal Component Analysis mathematical scaling.

LINEAR REGRESSION FIT · y = mx + b
y = 0.4000 · x
#Total Variance Scale Factor k (factor)First Principal Component Eigenvalue λ_1 (Eigenvalue λ_1)Total Variance Scale Factor kFirst Principal Component Eigenvalue λ_1Remove

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CHECK YOUR UNDERSTANDING

Explain what the statistical metrics mean.

In Principal Component Analysis, what matrix equation defines the first loading vector v_1 and its associated variance λ_1?

What does the Eckart-Young-Mirsky theorem prove about truncated SVD in PCA?

When should PCA be performed on the Correlation matrix rather than the raw Covariance matrix?

What does the Kaiser-Guttman criterion recommend for component retention in correlation-based PCA?