@stdlib/stats-base-dists-chisquare/README.md

Chi-squared distribution.

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# Chi-squared

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> Chi-squared distribution.

<section class="installation">

## Installation

```bash
npm install @stdlib/stats-base-dists-chisquare
```

</section>

<section class="usage">

## Usage

```javascript
var chisquare = require( '@stdlib/stats-base-dists-chisquare' );
```

#### chisquare

Chi-squared distribution.

```javascript
var dist = chisquare;
// returns {...}
```

The namespace contains the following distribution functions:

<!-- <toc pattern="*+(cdf|pdf|mgf|quantile)*"> -->

<div class="namespace-toc">

-   <span class="signature">[`cdf( x, k )`][@stdlib/stats/base/dists/chisquare/cdf]</span><span class="delimiter">: </span><span class="description">Chi-squared distribution cumulative distribution function.</span>
-   <span class="signature">[`logpdf( x, k )`][@stdlib/stats/base/dists/chisquare/logpdf]</span><span class="delimiter">: </span><span class="description">evaluate the natural logarithm of the probability density function (PDF) for a chi-squared distribution.</span>
-   <span class="signature">[`mgf( t, k )`][@stdlib/stats/base/dists/chisquare/mgf]</span><span class="delimiter">: </span><span class="description">Chi-squared distribution moment-generating function (MGF).</span>
-   <span class="signature">[`pdf( x, k )`][@stdlib/stats/base/dists/chisquare/pdf]</span><span class="delimiter">: </span><span class="description">Chi-squared distribution probability density function (PDF).</span>
-   <span class="signature">[`quantile( p, k )`][@stdlib/stats/base/dists/chisquare/quantile]</span><span class="delimiter">: </span><span class="description">Chi-squared distribution quantile function.</span>

</div>

<!-- </toc> -->

The namespace contains the following functions for calculating distribution properties:

<!-- <toc pattern="*+(entropy|kurtosis|mean|median|mode|skewness|stdev|variance)*"> -->

<div class="namespace-toc">

-   <span class="signature">[`entropy( k )`][@stdlib/stats/base/dists/chisquare/entropy]</span><span class="delimiter">: </span><span class="description">Chi-squared distribution differential entropy.</span>
-   <span class="signature">[`kurtosis( k )`][@stdlib/stats/base/dists/chisquare/kurtosis]</span><span class="delimiter">: </span><span class="description">Chi-squared distribution excess kurtosis.</span>
-   <span class="signature">[`mean( k )`][@stdlib/stats/base/dists/chisquare/mean]</span><span class="delimiter">: </span><span class="description">Chi-squared distribution expected value.</span>
-   <span class="signature">[`median( k )`][@stdlib/stats/base/dists/chisquare/median]</span><span class="delimiter">: </span><span class="description">Chi-squared distribution median.</span>
-   <span class="signature">[`mode( k )`][@stdlib/stats/base/dists/chisquare/mode]</span><span class="delimiter">: </span><span class="description">Chi-squared distribution mode.</span>
-   <span class="signature">[`skewness( k )`][@stdlib/stats/base/dists/chisquare/skewness]</span><span class="delimiter">: </span><span class="description">Chi-squared distribution skewness.</span>
-   <span class="signature">[`stdev( k )`][@stdlib/stats/base/dists/chisquare/stdev]</span><span class="delimiter">: </span><span class="description">Chi-squared distribution standard deviation.</span>
-   <span class="signature">[`variance( k )`][@stdlib/stats/base/dists/chisquare/variance]</span><span class="delimiter">: </span><span class="description">Chi-squared distribution variance.</span>

</div>

<!-- </toc> -->

The namespace contains a constructor function for creating a [Chi-squared][chisquare-distribution] distribution object.

<!-- <toc pattern="*ctor*"> -->

<div class="namespace-toc">

-   <span class="signature">[`ChiSquare( [k] )`][@stdlib/stats/base/dists/chisquare/ctor]</span><span class="delimiter">: </span><span class="description">Chi-squared distribution constructor.</span>

</div>

<!-- </toc> -->

```javascript
var ChiSquare = require( '@stdlib/stats-base-dists-chisquare' ).ChiSquare;

var dist = new ChiSquare( 4.0 );

var mu = dist.mean;
// returns 4.0
```

</section>

<!-- /.usage -->

<section class="examples">

## Examples

<!-- TODO: better examples -->

<!-- eslint no-undef: "error" -->

```javascript
var objectKeys = require( '@stdlib/utils-keys' );
var chisquare = require( '@stdlib/stats-base-dists-chisquare' );

console.log( objectKeys( chisquare ) );
```

</section>

<!-- /.examples -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

</section>

<!-- /.related -->

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<section class="main-repo" >

* * *

## 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].

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---

## License

See [LICENSE][stdlib-license].


## Copyright

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[chisquare-distribution]: https://en.wikipedia.org/wiki/Chi-squared_distribution

<!-- <toc-links> -->

[@stdlib/stats/base/dists/chisquare/ctor]: https://www.npmjs.com/package/@stdlib/stats-base-dists-chisquare-ctor

[@stdlib/stats/base/dists/chisquare/entropy]: https://www.npmjs.com/package/@stdlib/stats-base-dists-chisquare-entropy

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[@stdlib/stats/base/dists/chisquare/mode]: https://www.npmjs.com/package/@stdlib/stats-base-dists-chisquare-mode

[@stdlib/stats/base/dists/chisquare/skewness]: https://www.npmjs.com/package/@stdlib/stats-base-dists-chisquare-skewness

[@stdlib/stats/base/dists/chisquare/stdev]: https://www.npmjs.com/package/@stdlib/stats-base-dists-chisquare-stdev

[@stdlib/stats/base/dists/chisquare/variance]: https://www.npmjs.com/package/@stdlib/stats-base-dists-chisquare-variance

[@stdlib/stats/base/dists/chisquare/cdf]: https://www.npmjs.com/package/@stdlib/stats-base-dists-chisquare-cdf

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[@stdlib/stats/base/dists/chisquare/quantile]: https://www.npmjs.com/package/@stdlib/stats-base-dists-chisquare-quantile

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