Arithmetic Mean

Install and import#

bash

npm install fintech-algorithms

import { arithmeticMean } from "fintech-algorithms/foundations/location-ranking-and-exploratory-summaries/arithmetic-mean";

arithmeticMean(input)

Divides the sum of a numeric series by the number of observations and reports both the mean and the count it was divided by.

Name	Type	Notes
`input`	`{ values: number[] }`	The observations to average, under the key `values`. Entries are coerced with `Number`, and every one must be finite.

{ mean: number; count: number }

mean is the arithmetic average and count is the divisor used, so the reader can see how many observations stand behind the number.

When input is null, an array, or not an object — throws TypeError
When values is missing, is not an array, or is empty — throws RangeError
When any entry of values does not coerce to a finite number — throws RangeError

Complexity: time O(n log n), space O(n).

verified This is the worked example published in the article, replayed by the test suite on every run. The output cannot drift.

input

{
  "values": [1, 2, 2, 4, 9],
  "weights": [1, 1, 2, 1, 1],
  "trimProportion": 0.2,
  "bins": 4
}

arithmeticMean(input)

object with 2 fields: mean, count

{
  "mean": 3.6,
  "count": 5
}

This page states the contract — how to call it correctly. The article explains the concept: why it works, and where it breaks.