als-statistics/lib/analyze/compare-means/paired.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 CDF from '../cdf/index.js';
import { TestBase } from '../test-base/index.js'

export class PairedTTest extends TestBase {
   constructor(samples) {
      super(samples, 'Paired T-Test', ['t', 'p', 'meanDelta', 'sdDelta', 'n', 'df'], { min: 2, sameSize: true })
      this.#calc()
   }

   #calc() {
      this.diffs = this.samples[0].values.map((v, i) => v - this.samples[1].values[i])
      this.meanDelta = this.diffs.reduce((t, v) => t + v, 0) / this.n
      let ss = 0;
      for (let i = 0; i < this.n; i++) ss += Math.pow(this.diffs[i] - this.meanDelta, 2);
      this.sdDelta = Math.sqrt(ss / (this.n - 1));
      this.t = this.meanDelta / (this.sdDelta / Math.sqrt(this.n));
      this.df = this.n - 1;
   }

   get p() { return 2 * (1 - CDF.t(Math.abs(this.t), this.df)) }
}