als-statistics/tests/golden/edge-cronbach.test.js

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

import test from 'node:test';
import assert from 'node:assert/strict';
import {CronbachAlpha} from '../../lib/analyze/correlate/cronbach-alpha.js';

test('Cronbach: perfect reliability on identical items', () => {
  const items = { A:[1,2,3,4,5], B:[1,2,3,4,5], C:[1,2,3,4,5] };
  const alpha = new CronbachAlpha(items);
  assert.ok(alpha.alpha > 0.95);
  const deleted = alpha.ifItemsDeleted;
  assert.equal(typeof deleted, 'object');
  assert.ok(Object.keys(deleted).includes('A'));
  assert.ok(alpha.htmlTable.includes('<table'));
});

test('Cronbach: negative alpha on contrary item', () => {
  const items = { A:[1,2,3,4,5], B:[5,4,3,2,1] }; // противофаза
  const alpha = new CronbachAlpha(items);
  assert.ok(alpha.alpha <= 0);
});