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Chi
Chi distribution constructor.
Installation
npm install @stdlib/stats-base-dists-chi-ctor
Usage
var Chi = require( '@stdlib/stats-base-dists-chi-ctor' );
Chi( [k] )
Returns an chi distribution object.
var chi = new Chi();
var mu = chi.mean;
// returns ~0.798
By default, k = 1.0
. To create a distribution having a different degrees of freedom k
, provide a parameter value.
var chi = new Chi( 4.0 );
var mu = chi.mean;
// returns ~1.88
chi
A chi distribution object has the following properties and methods...
Writable Properties
chi.k
Degrees of freedom of the distribution. k
must be a positive number.
var chi = new Chi( 2.0 );
var k = chi.k;
// returns 2.0
chi.k = 3.0;
k = chi.k;
// returns 3.0
Computed Properties
Chi.prototype.entropy
Returns the differential entropy.
var chi = new Chi( 4.0 );
var entropy = chi.entropy;
// returns ~1.019
Chi.prototype.kurtosis
Returns the excess kurtosis.
var chi = new Chi( 4.0 );
var kurtosis = chi.kurtosis;
// returns ~0.059
Chi.prototype.mean
Returns the expected value.
var chi = new Chi( 4.0 );
var mu = chi.mean;
// returns ~1.88
Chi.prototype.mode
Returns the mode.
var chi = new Chi( 4.0 );
var mode = chi.mode;
// returns ~1.732
Chi.prototype.skewness
Returns the skewness.
var chi = new Chi( 4.0 );
var skewness = chi.skewness;
// returns ~0.406
Chi.prototype.stdev
Returns the standard deviation.
var chi = new Chi( 4.0 );
var s = chi.stdev;
// returns ~0.682
Chi.prototype.variance
Returns the variance.
var chi = new Chi( 4.0 );
var s2 = chi.variance;
// returns ~0.466
Methods
Chi.prototype.cdf( x )
Evaluates the cumulative distribution function (CDF).
var chi = new Chi( 2.0 );
var y = chi.cdf( 0.5 );
// returns ~0.118
Chi.prototype.logpdf( x )
Evaluates the natural logarithm of the probability density function (PDF).
var chi = new Chi( 2.0 );
var y = chi.logpdf( 0.8 );
// returns ~-0.543
Chi.prototype.pdf( x )
Evaluates the probability density function (PDF).
var chi = new Chi( 2.0 );
var y = chi.pdf( 0.8 );
// returns ~0.581
Chi.prototype.quantile( p )
Evaluates the quantile function at probability p
.
var chi = new Chi( 2.0 );
var y = chi.quantile( 0.5 );
// returns ~1.177
y = chi.quantile( 1.9 );
// returns NaN
Examples
var Chi = require( '@stdlib/stats-base-dists-chi-ctor' );
var chi = new Chi( 2.0 );
var mu = chi.mean;
// returns ~1.253
var mode = chi.mode;
// returns 1.0
var s2 = chi.variance;
// returns ~0.429
var y = chi.cdf( 0.8 );
// returns ~0.274
Notice
This package is part of 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, see the main project repository.
Community
License
See LICENSE.
Copyright
Copyright © 2016-2024. The Stdlib Authors.