# Chi-squared > Chi-squared distribution.
## 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:
- [`cdf( x, k )`][@stdlib/stats/base/dists/chisquare/cdf]: Chi-squared distribution cumulative distribution function. - [`logpdf( x, k )`][@stdlib/stats/base/dists/chisquare/logpdf]: evaluate the natural logarithm of the probability density function (PDF) for a chi-squared distribution. - [`mgf( t, k )`][@stdlib/stats/base/dists/chisquare/mgf]: Chi-squared distribution moment-generating function (MGF). - [`pdf( x, k )`][@stdlib/stats/base/dists/chisquare/pdf]: Chi-squared distribution probability density function (PDF). - [`quantile( p, k )`][@stdlib/stats/base/dists/chisquare/quantile]: Chi-squared distribution quantile function.
The namespace contains the following functions for calculating distribution properties:
- [`entropy( k )`][@stdlib/stats/base/dists/chisquare/entropy]: Chi-squared distribution differential entropy. - [`kurtosis( k )`][@stdlib/stats/base/dists/chisquare/kurtosis]: Chi-squared distribution excess kurtosis. - [`mean( k )`][@stdlib/stats/base/dists/chisquare/mean]: Chi-squared distribution expected value. - [`median( k )`][@stdlib/stats/base/dists/chisquare/median]: Chi-squared distribution median. - [`mode( k )`][@stdlib/stats/base/dists/chisquare/mode]: Chi-squared distribution mode. - [`skewness( k )`][@stdlib/stats/base/dists/chisquare/skewness]: Chi-squared distribution skewness. - [`stdev( k )`][@stdlib/stats/base/dists/chisquare/stdev]: Chi-squared distribution standard deviation. - [`variance( k )`][@stdlib/stats/base/dists/chisquare/variance]: Chi-squared distribution variance.
The namespace contains a constructor function for creating a [Chi-squared][chisquare-distribution] distribution object.
- [`ChiSquare( [k] )`][@stdlib/stats/base/dists/chisquare/ctor]: Chi-squared distribution constructor.
```javascript var ChiSquare = require( '@stdlib/stats/base/dists/chisquare' ).ChiSquare; var dist = new ChiSquare( 4.0 ); var mu = dist.mean; // returns 4.0 ```
## Examples ```javascript var objectKeys = require( '@stdlib/utils/keys' ); var chisquare = require( '@stdlib/stats/base/dists/chisquare' ); console.log( objectKeys( chisquare ) ); ```