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    0.0.8 • Public • Published

    ChiSquare

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    Chi-squared distribution constructor.

    Installation

    npm install @stdlib/stats-base-dists-chisquare-ctor

    Usage

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

    ChiSquare( [k] )

    Returns an chi-squared distribution object.

    var chisquare = new ChiSquare();
    
    var mu = chisquare.mean;
    // returns 1.0

    By default, k = 1.0. To create a distribution having a different degrees of freedom k, provide a parameter value.

    var chisquare = new ChiSquare( 4.0 );
    
    var mu = chisquare.mean;
    // returns 4.0

    chisquare

    A chi-squared distribution object has the following properties and methods...

    Writable Properties

    chisquare.k

    Rate parameter of the distribution. k must be a positive number.

    var chisquare = new ChiSquare( 2.0 );
    
    var k = chisquare.k;
    // returns 2.0
    
    chisquare.k = 3.0;
    
    k = chisquare.k;
    // returns 3.0

    Computed Properties

    ChiSquare.prototype.entropy

    Returns the differential entropy.

    var chisquare = new ChiSquare( 4.0 );
    
    var entropy = chisquare.entropy;
    // returns ~2.27

    ChiSquare.prototype.kurtosis

    Returns the excess kurtosis.

    var chisquare = new ChiSquare( 4.0 );
    
    var kurtosis = chisquare.kurtosis;
    // returns 3.0

    ChiSquare.prototype.mean

    Returns the expected value.

    var chisquare = new ChiSquare( 4.0 );
    
    var mu = chisquare.mean;
    // returns 4.0

    ChiSquare.prototype.median

    Returns the median.

    var chisquare = new ChiSquare( 4.0 );
    
    var median = chisquare.median;
    // returns ~3.357

    ChiSquare.prototype.mode

    Returns the mode.

    var chisquare = new ChiSquare( 4.0 );
    
    var mode = chisquare.mode;
    // returns 2.0

    ChiSquare.prototype.skewness

    Returns the skewness.

    var chisquare = new ChiSquare( 4.0 );
    
    var skewness = chisquare.skewness;
    // returns ~1.414

    ChiSquare.prototype.stdev

    Returns the standard deviation.

    var chisquare = new ChiSquare( 4.0 );
    
    var s = chisquare.stdev;
    // returns ~2.828

    ChiSquare.prototype.variance

    Returns the variance.

    var chisquare = new ChiSquare( 4.0 );
    
    var s2 = chisquare.variance;
    // returns 8.0

    Methods

    ChiSquare.prototype.cdf( x )

    Evaluates the cumulative distribution function (CDF).

    var chisquare = new ChiSquare( 2.0 );
    
    var y = chisquare.cdf( 0.5 );
    // returns ~0.221

    ChiSquare.prototype.mgf( t )

    Evaluates the moment-generating function (MGF).

    var chisquare = new ChiSquare( 2.0 );
    
    var y = chisquare.mgf( 0.2 );
    // returns ~1.667

    ChiSquare.prototype.pdf( x )

    Evaluates the probability density function (PDF).

    var chisquare = new ChiSquare( 2.0 );
    
    var y = chisquare.pdf( 0.8 );
    // returns ~0.335

    ChiSquare.prototype.quantile( p )

    Evaluates the quantile function at probability p.

    var chisquare = new ChiSquare( 2.0 );
    
    var y = chisquare.quantile( 0.5 );
    // returns ~1.386
    
    y = chisquare.quantile( 1.9 );
    // returns NaN

    Examples

    var ChiSquare = require( '@stdlib/stats-base-dists-chisquare-ctor' );
    
    var chisquare = new ChiSquare( 2.0 );
    
    var mu = chisquare.mean;
    // returns 2.0
    
    var mode = chisquare.mode;
    // returns 0.0
    
    var s2 = chisquare.variance;
    // returns 4.0
    
    var y = chisquare.cdf( 0.8 );
    // returns ~0.33

    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

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    License

    See LICENSE.

    Copyright

    Copyright © 2016-2022. The Stdlib Authors.

    Install

    npm i @stdlib/stats-base-dists-chisquare-ctor

    Homepage

    stdlib.io

    DownloadsWeekly Downloads

    44

    Version

    0.0.8

    License

    Apache-2.0

    Unpacked Size

    38 kB

    Total Files

    9

    Last publish

    Collaborators

    • stdlib-bot
    • kgryte
    • planeshifter
    • rreusser