项目作者: stdlib-js

项目描述 :
Kumaraswamy's double bounded distribution constructor.
高级语言: JavaScript
项目地址: git://github.com/stdlib-js/stats-base-dists-kumaraswamy-ctor.git
创建时间: 2021-06-15T17:40:57Z
项目社区:https://github.com/stdlib-js/stats-base-dists-kumaraswamy-ctor

开源协议:Apache License 2.0

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Kumaraswamy

[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]

Kumaraswamy’s double bounded distribution constructor.





## Installation

bash npm install @stdlib/stats-base-dists-kumaraswamy-ctor

Alternatively,

- To load the package in a website via a script tag without installation and bundlers, use the [ES Module][es-module] available on the [esm][esm-url] branch (see [README][esm-readme]).
- If you are using Deno, visit the [deno][deno-url] branch (see [README][deno-readme] for usage intructions).
- For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [umd][umd-url] branch (see [README][umd-readme]).

The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.



## Usage

javascript var Kumaraswamy = require( '@stdlib/stats-base-dists-kumaraswamy-ctor' );

#### Kumaraswamy( [a, b] )

Returns a [Kumaraswamy’s double bounded][kumaraswamy-distribution] distribution object.

javascript var kumaraswamy = new Kumaraswamy(); var mu = kumaraswamy.mean; // returns 0.5

By default, a = 1.0 and b = 1.0. To create a distribution having a different a (first shape parameter) and b (second shape parameter), provide the corresponding arguments.

javascript var kumaraswamy = new Kumaraswamy( 2.0, 4.0 ); var mu = kumaraswamy.mean; // returns ~0.406



## kumaraswamy

A [Kumaraswamy’s double bounded][kumaraswamy-distribution] distribution object has the following properties and methods…

### Writable Properties

#### kumaraswamy.a

First shape parameter of the distribution. a must be a positive number.

javascript var kumaraswamy = new Kumaraswamy(); var a = kumaraswamy.a; // returns 1.0 kumaraswamy.a = 3.0; a = kumaraswamy.a; // returns 3.0

#### kumaraswamy.b

Second shape parameter of the distribution. b must be a positive number.

javascript var kumaraswamy = new Kumaraswamy( 2.0, 4.0 ); var b = kumaraswamy.b; // returns 4.0 kumaraswamy.b = 3.0; b = kumaraswamy.b; // returns 3.0


### Computed Properties

#### Kumaraswamy.prototype.kurtosis

Returns the [excess kurtosis][kurtosis].

javascript var kumaraswamy = new Kumaraswamy( 4.0, 12.0 ); var kurtosis = kumaraswamy.kurtosis; // returns ~2.704

#### Kumaraswamy.prototype.mean

Returns the [expected value][expected-value].

javascript var kumaraswamy = new Kumaraswamy( 4.0, 12.0 ); var mu = kumaraswamy.mean; // returns ~0.481

#### Kumaraswamy.prototype.mode

Returns the [mode][mode].

javascript var kumaraswamy = new Kumaraswamy( 4.0, 12.0 ); var mode = kumaraswamy.mode; // returns ~0.503

#### Kumaraswamy.prototype.skewness

Returns the [skewness][skewness].

javascript var kumaraswamy = new Kumaraswamy( 4.0, 12.0 ); var skewness = kumaraswamy.skewness; // returns ~-0.201

#### Kumaraswamy.prototype.stdev

Returns the [standard deviation][standard-deviation].

javascript var kumaraswamy = new Kumaraswamy( 4.0, 12.0 ); var s = kumaraswamy.stdev; // returns ~0.13

#### Kumaraswamy.prototype.variance

Returns the [variance][variance].

javascript var kumaraswamy = new Kumaraswamy( 4.0, 12.0 ); var s2 = kumaraswamy.variance; // returns ~0.017

*

### Methods

#### Kumaraswamy.prototype.cdf( x )

Evaluates the [cumulative distribution function][cdf] (CDF).

javascript var kumaraswamy = new Kumaraswamy( 2.0, 4.0 ); var y = kumaraswamy.cdf( 0.5 ); // returns ~0.684

#### Kumaraswamy.prototype.logcdf( x )

Evaluates the natural logarithm of the [cumulative distribution function][cdf] (CDF).

javascript var kumaraswamy = new Kumaraswamy( 2.0, 4.0 ); var y = kumaraswamy.logcdf( 0.5 ); // returns ~-0.38

#### Kumaraswamy.prototype.logpdf( x )

Evaluates the natural logarithm of the [probability density function][pdf] (PDF).

javascript var kumaraswamy = new Kumaraswamy( 2.0, 4.0 ); var y = kumaraswamy.logpdf( 0.8 ); // returns ~-1.209

#### Kumaraswamy.prototype.pdf( x )

Evaluates the [probability density function][pdf] (PDF).

javascript var kumaraswamy = new Kumaraswamy( 2.0, 4.0 ); var y = kumaraswamy.pdf( 0.8 ); // returns ~0.299

#### Kumaraswamy.prototype.quantile( p )

Evaluates the [quantile function][quantile-function] at probability p.

javascript var kumaraswamy = new Kumaraswamy( 2.0, 4.0 ); var y = kumaraswamy.quantile( 0.5 ); // returns ~0.399 y = kumaraswamy.quantile( 1.9 ); // returns NaN






## Examples



javascript var Kumaraswamy = require( '@stdlib/stats-base-dists-kumaraswamy-ctor' ); var kumaraswamy = new Kumaraswamy( 2.0, 4.0 ); var mu = kumaraswamy.mean; // returns ~0.406 var mode = kumaraswamy.mode; // returns ~0.378 var s2 = kumaraswamy.variance; // returns ~0.035 var y = kumaraswamy.cdf( 0.8 ); // returns ~0.983





*

## Notice

This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].

#### Community

[![Chat][chat-image]][chat-url]

—-

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright © 2016-2025. The Stdlib [Authors][stdlib-authors].