## Usage
```javascript
var invgamma = require( '@stdlib/stats/base/dists/invgamma' );
```
#### invgamma
Inverse gamma distribution.
```javascript
var dist = invgamma;
// returns {...}
```
The namespace contains the following distribution functions:
- [`cdf( x, alpha, beta )`][@stdlib/stats/base/dists/invgamma/cdf]: inverse Gamma distribution cumulative distribution function.
- [`logpdf( x, alpha, beta )`][@stdlib/stats/base/dists/invgamma/logpdf]: evaluate the natural logarithm of the probability density function (PDF) for an inverse gamma distribution.
- [`pdf( x, alpha, beta )`][@stdlib/stats/base/dists/invgamma/pdf]: inverse gamma distribution probability density function (PDF).
- [`quantile( p, alpha, beta )`][@stdlib/stats/base/dists/invgamma/quantile]: inverse gamma distribution quantile function.
The namespace contains the following functions for calculating distribution properties:
- [`entropy( alpha, beta )`][@stdlib/stats/base/dists/invgamma/entropy]: inverse gamma distribution differential entropy.
- [`kurtosis( alpha, beta )`][@stdlib/stats/base/dists/invgamma/kurtosis]: inverse gamma distribution excess kurtosis.
- [`mean( alpha, beta )`][@stdlib/stats/base/dists/invgamma/mean]: inverse gamma distribution expected value.
- [`mode( alpha, beta )`][@stdlib/stats/base/dists/invgamma/mode]: inverse gamma distribution mode.
- [`skewness( alpha, beta )`][@stdlib/stats/base/dists/invgamma/skewness]: inverse gamma distribution skewness.
- [`stdev( alpha, beta )`][@stdlib/stats/base/dists/invgamma/stdev]: inverse gamma distribution standard deviation.
- [`variance( alpha, beta )`][@stdlib/stats/base/dists/invgamma/variance]: inverse gamma distribution variance.
The namespace contains a constructor function for creating a [inverse gamma][invgamma-distribution] distribution object.
- [`InvGamma( [alpha, beta] )`][@stdlib/stats/base/dists/invgamma/ctor]: inverse gamma distribution constructor.
```javascript
var InvGamma = require( '@stdlib/stats/base/dists/invgamma' ).InvGamma;
var dist = new InvGamma( 2.0, 4.0 );
var y = dist.cdf( 0.5 );
// returns ~0.003
```