@stdlib/stats-base-dists-lognormal-ctor
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    0.0.6 • Public • Published

    Lognormal

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    Lognormal distribution constructor.

    Installation

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

    Usage

    var LogNormal = require( '@stdlib/stats-base-dists-lognormal-ctor' );

    LogNormal( [mu, sigma] )

    Returns a lognormal distribution object.

    var lognormal = new LogNormal();
    
    var mean = lognormal.mean;
    // returns ~1.649

    By default, mu = 0.0 and sigma = 1.0. To create a distribution having a different mu (location parameter) and sigma (scale parameter), provide the corresponding arguments.

    var lognormal = new LogNormal( 2.0, 4.0 );
    
    var mu = lognormal.mean;
    // returns ~22026.466

    lognormal

    A lognormal distribution object has the following properties and methods...

    Writable Properties

    lognormal.mu

    Location parameter of the distribution.

    var lognormal = new LogNormal();
    
    var mu = lognormal.mu;
    // returns 0.0
    
    lognormal.mu = 3.0;
    
    mu = lognormal.mu;
    // returns 3.0

    lognormal.sigma

    Scale parameter of the distribution. sigma must be a positive number.

    var lognormal = new LogNormal( 2.0, 4.0 );
    
    var sigma = lognormal.sigma;
    // returns 4.0
    
    lognormal.sigma = 3.0;
    
    sigma = lognormal.sigma;
    // returns 3.0

    Computed Properties

    LogNormal.prototype.entropy

    Returns the differential entropy.

    var lognormal = new LogNormal( 4.0, 12.0 );
    
    var entropy = lognormal.entropy;
    // returns ~7.904

    LogNormal.prototype.kurtosis

    Returns the excess kurtosis.

    var lognormal = new LogNormal( 4.0, 12.0 );
    
    var kurtosis = lognormal.kurtosis;
    // returns 1.4243659274306933e+250

    LogNormal.prototype.mean

    Returns the expected value.

    var lognormal = new LogNormal( 4.0, 12.0 );
    
    var mu = lognormal.mean;
    // returns 1.0148003881138887e+33

    LogNormal.prototype.median

    Returns the median.

    var lognormal = new LogNormal( 4.0, 12.0 );
    
    var median = lognormal.median;
    // returns ~54.598

    LogNormal.prototype.mode

    Returns the mode.

    var lognormal = new LogNormal( 4.0, 12.0 );
    
    var mode = lognormal.mode;
    // returns 1.580420060273613e-61

    LogNormal.prototype.skewness

    Returns the skewness.

    var lognormal = new LogNormal( 4.0, 12.0 );
    
    var skewness = lognormal.skewness;
    // returns 6.421080152185613e+93

    LogNormal.prototype.stdev

    Returns the standard deviation.

    var lognormal = new LogNormal( 4.0, 12.0 );
    
    var s = lognormal.stdev;
    // returns 1.886180808490652e+64

    LogNormal.prototype.variance

    Returns the variance.

    var lognormal = new LogNormal( 4.0, 12.0 );
    
    var s2 = lognormal.variance;
    // returns 3.55767804231845e+128

    Methods

    LogNormal.prototype.cdf( x )

    Evaluates the cumulative distribution function (CDF).

    var lognormal = new LogNormal( 2.0, 4.0 );
    
    var y = lognormal.cdf( 0.5 );
    // returns ~0.25

    LogNormal.prototype.logpdf( x )

    Evaluates the natural logarithm of the probability density function (PDF).

    var lognormal = new LogNormal( 2.0, 4.0 );
    
    var y = lognormal.logpdf( 2.0 );
    // returns ~-3.052

    LogNormal.prototype.pdf( x )

    Evaluates the probability density function (PDF).

    var lognormal = new LogNormal( 2.0, 4.0 );
    
    var y = lognormal.pdf( 2.0 );
    // returns ~0.047

    LogNormal.prototype.quantile( p )

    Evaluates the quantile function at probability p.

    var lognormal = new LogNormal( 2.0, 4.0 );
    
    var y = lognormal.quantile( 0.5 );
    // returns ~7.389
    
    y = lognormal.quantile( 1.9 );
    // returns NaN

    Examples

    var LogNormal = require( '@stdlib/stats-base-dists-lognormal-ctor' );
    
    var lognormal = new LogNormal( 2.0, 1.0 );
    
    var mean = lognormal.mean;
    // returns ~12.182
    
    var median = lognormal.median;
    // returns ~7.389
    
    var s2 = lognormal.variance;
    // returns ~255.016
    
    var y = lognormal.cdf( 0.8 );
    // returns ~0.013

    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.

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    License

    See LICENSE.

    Copyright

    Copyright © 2016-2021. The Stdlib Authors.

    Install

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

    Homepage

    stdlib.io

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