https://github.com/stdlib-js/stats-base-dists-kumaraswamy-mean
Kumaraswamy's double bounded distribution expected value.
https://github.com/stdlib-js/stats-base-dists-kumaraswamy-mean
average avg center continuous dist distribution expected javascript kumaraswamy location mean moments node node-js nodejs prob probability statistics stats stdlib
Last synced: 8 months ago
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Kumaraswamy's double bounded distribution expected value.
- Host: GitHub
- URL: https://github.com/stdlib-js/stats-base-dists-kumaraswamy-mean
- Owner: stdlib-js
- License: apache-2.0
- Created: 2021-06-15T17:40:48.000Z (almost 5 years ago)
- Default Branch: main
- Last Pushed: 2025-02-03T01:55:14.000Z (over 1 year ago)
- Last Synced: 2025-03-02T05:12:31.458Z (over 1 year ago)
- Topics: average, avg, center, continuous, dist, distribution, expected, javascript, kumaraswamy, location, mean, moments, node, node-js, nodejs, prob, probability, statistics, stats, stdlib
- Language: JavaScript
- Homepage: https://github.com/stdlib-js/stdlib
- Size: 973 KB
- Stars: 2
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Code of conduct: CODE_OF_CONDUCT.md
- Citation: CITATION.cff
- Security: SECURITY.md
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README
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# Mean
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> [Kumaraswamy's double bounded][kumaraswamy-distribution] distribution [expected value][mean].
The [mean][mean] for a [Kumaraswamy's double bounded][kumaraswamy-distribution] random variable is
```math
\mathbb{E} \left[ X \right] = {b\Gamma(1+{\tfrac {1}{a}})\Gamma(b)}{\Gamma(1+{\tfrac{1}{a}}+b)}
```
where `a` is the first shape parameter, `b` the second shape parameter, and `Γ` denotes the [gamma function][gamma-function].
## Installation
```bash
npm install @stdlib/stats-base-dists-kumaraswamy-mean
```
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 mean = require( '@stdlib/stats-base-dists-kumaraswamy-mean' );
```
#### mean( a, b )
Returns the [expected value][mean] of a [Kumaraswamy's double bounded][kumaraswamy-distribution] distribution with first shape parameter `a` and second shape parameter `b`.
```javascript
var v = mean( 1.5, 1.5 );
// returns ~0.512
v = mean( 4.0, 12.0 );
// returns ~0.481
v = mean( 2.0, 8.0 );
// returns ~0.3
```
If provided `NaN` as any argument, the function returns `NaN`.
```javascript
var v = mean( NaN, 2.0 );
// returns NaN
v = mean( 2.0, NaN );
// returns NaN
```
If provided `a <= 0`, the function returns `NaN`.
```javascript
var y = mean( -1.0, 2.0 );
// returns NaN
y = mean( 0.0, 2.0 );
// returns NaN
```
If provided `b <= 0`, the function returns `NaN`.
```javascript
var y = mean( 2.0, -1.0 );
// returns NaN
y = mean( 2.0, 0.0 );
// returns NaN
```
## Examples
```javascript
var uniform = require( '@stdlib/random-array-uniform' );
var logEachMap = require( '@stdlib/console-log-each-map' );
var mean = require( '@stdlib/stats-base-dists-kumaraswamy-mean' );
var opts = {
'dtype': 'float64'
};
var a = uniform( 10, 0.0, 10.0, opts );
var b = uniform( 10, 0.0, 10.0, opts );
logEachMap( 'a: %0.4f, b: %0.4f, E(X;a,b): %0.4f', a, b, mean );
```
* * *
## C APIs
### Usage
```c
#include "stdlib/stats/base/dists/kumaraswamy/mean.h"
```
#### stdlib_base_dists_kumaraswamy_mean( a, b )
Returns the [expected value][mean] of a [Kumaraswamy's double bounded][kumaraswamy-distribution] distribution with first shape parameter `a` and second shape parameter `b`.
```c
double out = stdlib_base_dists_kumaraswamy_mean( 1.5, 1.5 );
// returns ~0.512
```
The function accepts the following arguments:
- **a**: `[in] double` first shape parameter.
- **b**: `[in] double` second shape parameter.
```c
double stdlib_base_dists_kumaraswamy_mean( const double a, const double b );
```
### Examples
```c
#include "stdlib/stats/base/dists/kumaraswamy/mean.h"
#include
#include
static double random_uniform( const double min, const double max ) {
double v = (double)rand() / ( (double)RAND_MAX + 1.0 );
return min + ( v*(max-min) );
}
int main( void ) {
double mean;
double a;
double b;
int i;
for ( i = 0; i < 10; i++ ) {
a = random_uniform( 0.0, 10.0 );
b = random_uniform( 0.0, 10.0 );
mean = stdlib_base_dists_kumaraswamy_mean( a, b );
printf( "a: %.4f, b: %.4f, E(X;a,b): %.4f\n", a, b, mean );
}
}
```
* * *
## 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].
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[npm-url]: https://npmjs.org/package/@stdlib/stats-base-dists-kumaraswamy-mean
[test-image]: https://github.com/stdlib-js/stats-base-dists-kumaraswamy-mean/actions/workflows/test.yml/badge.svg?branch=main
[test-url]: https://github.com/stdlib-js/stats-base-dists-kumaraswamy-mean/actions/workflows/test.yml?query=branch:main
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[coverage-url]: https://codecov.io/github/stdlib-js/stats-base-dists-kumaraswamy-mean?branch=main
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[stdlib]: https://github.com/stdlib-js/stdlib
[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors
[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/stats-base-dists-kumaraswamy-mean/tree/deno
[deno-readme]: https://github.com/stdlib-js/stats-base-dists-kumaraswamy-mean/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/stats-base-dists-kumaraswamy-mean/tree/umd
[umd-readme]: https://github.com/stdlib-js/stats-base-dists-kumaraswamy-mean/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/stats-base-dists-kumaraswamy-mean/tree/esm
[esm-readme]: https://github.com/stdlib-js/stats-base-dists-kumaraswamy-mean/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/stats-base-dists-kumaraswamy-mean/blob/main/branches.md
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/stats-base-dists-kumaraswamy-mean/main/LICENSE
[gamma-function]: https://en.wikipedia.org/wiki/Gamma_function
[kumaraswamy-distribution]: https://en.wikipedia.org/wiki/Kumaraswamy_distribution
[mean]: https://en.wikipedia.org/wiki/Mean