Add an algorithm to find mean absolute deviation

prashalruchiranga · prashalruchiranga · commit 687b505a761f · 2022-10-11T07:57:33.000+05:30
diff --git a/Maths/MeanAbsoluteDeviation.js b/Maths/MeanAbsoluteDeviation.js
@@ -0,0 +1,19 @@
+import { mean } from "./AverageMean.js"
+/**
+ *@function meanAbsoluteDeviation
+ *@description Calculates the mean absolute deviation of list of numbers
+ * @param {Integer} data
+ * @returns meanAbsoluteDeviation([2,34,5,0,-2]) = 10.480
+ * @url https://en.wikipedia.org/wiki/Average_absolute_deviation
+ */
+function meanAbsoluteDeviation (data) {
+  if (!Array.isArray(data)) {
+    throw new TypeError('Invalid Input')
+  }
+  let absoluteSum = 0
+  let meanValue = mean(data)
+  for (const dataPoint of data) {
+    absoluteSum += Math.abs(dataPoint - meanValue)
+  }
+  return (absoluteSum / data.length).toFixed(3)
+}
diff --git a/Maths/test/MeanAbsoluteDeviation.test.js b/Maths/test/MeanAbsoluteDeviation.test.js
@@ -0,0 +1,16 @@
+import {meanAbsoluteDeviation} from '../MeanAbsoluteDeviation.js'
+
+describe('tests for mean absolute deviation', () => {
+  it('should be a function', () => {
+    expect(typeof meanAbsoluteDeviation).toEqual('function')
+  })
+
+  it('should throw an invalid input error', () => {
+    expect(() => meanAbsoluteDeviation('fgh')).toThrow()
+  })
+
+  it('should return the mean absolute devition of an array of numbers', () => {
+    const meanAbDev = meanAbsoluteDeviation([2,34,5,0,-2])
+    expect(meanAbDev).toBe(10.480)
+  })
+})
