Five-Number Summary and Box Plot
Install and import#
npm install fintech-algorithmsimport { fiveNumberSummaryAndBoxPlot } from "fintech-algorithms/foundations/location-ranking-and-exploratory-summaries/five-number-summary-and-box-plot";Signature#
fiveNumberSummaryAndBoxPlot(input)Produces the minimum, three quartiles, and maximum of a numeric series, the Tukey 1.5-IQR fences drawn from them, and the observations lying outside those fences.
Parameters#
| Name | Type | Notes |
|---|---|---|
input | { values: number[] } | The observations to summarise, under the key values. Quartiles use linear interpolation between neighbouring order statistics. |
Returns#
{ fiveNumberSummary: number[]; fences: [number, number]; outliers: number[] }
fiveNumberSummary is [minimum, q1, median, q3, maximum], fences is [q1 - 1.5 * iqr, q3 + 1.5 * iqr], and outliers lists the observations strictly outside the fences in the caller's original order.
Errors#
- When
inputis null, an array, or not an object — throws TypeError - When
valuesis missing, is not an array, or is empty — throws RangeError - When any entry of
valuesdoes not coerce to a finite number — throws RangeError
Complexity: time O(n log n),
space O(n).
Worked example#
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
}Call#
fiveNumberSummaryAndBoxPlot(input)Returns#
object with 2 fields: fiveNumberSummary, fences
{
"fiveNumberSummary": [1, 2, 2, 4, 9],
"fences": [-1, 7]
}Diagrams#
How it works#
This page states the contract — how to call it correctly. The article explains the concept: why it works, and where it breaks.
References#
- Box Plot
- Percentile Definitions
- Historical-example decision