als-statistics/docs/03-analyze/readme.md

Modular JS statistics toolkit for Node.js and the browser: descriptive stats, correlations (Pearson/Spearman/Kendall), t-tests & ANOVA (Student/Welch), reliability (Cronbach’s alpha), regression (linear/logistic), clustering (DBSCAN/HDBSCAN), and table/co

<title>Analyze — Overview & Patterns</title>
<description>Connecting Tables to analyses with concise flows: correlations, mean comparisons, clustering, and regressions.</description>
<keywords>analyze, correlate, compare means, regression, clustering, pipeline</keywords>

# Analyze — overview & patterns

This section ties together the shortcuts across `Table`, `Statistics`, and `Analyze`.

## From Table to analysis

```js
import { Table } from 'als-statistics';
import { Analyze } from 'als-statistics';

const t = new Table(data, { name: 'Survey' });

// Correlation (single pair)
const r1 = t.correlate('height','weight').pearson();

// Correlation matrix (3+ columns)
const rAll = t.correlate('height','weight','age').pearson();

// Compare means (Welch, unequal variances)
const w  = t.compareMeans('groupA','groupB').independentWelch();

// One-way ANOVA (classic/Welch)
const a1 = t.compareMeans('A','B','C').anova();
const aW = t.compareMeans('A','B','C').anovaWelch();

// Regression (linear/logistic)
const lin = new Analyze.Regression(t.columns, { yName:'score', xNames:['age','hours'] });
const log = new Analyze.Regression(t.columns, { yName:'passed', xNames:['score'], type:'logistic' });
```

## Split → Combine (Statistics) → Analyze

```js
// Split one table by a factor (returns Statistics with per-group tables)
const S = t.splitBy('group', { 0:'ctrl', 1:'treat' });

// Combine the same column across all split tables into one Table
const merged = S.columns('byGroup', 'score'); // -> ctrl_score, treat_score

// Now analyze as usual
const test = merged.compareMeans('ctrl_score','treat_score').independentWelch();
```

> Keep **mutations** API-only (`addRow`, `setAt`, `splice`, `values=`). Avoid in-place array edits to preserve caches and consistent results.