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

    Mean

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    Lognormal distribution expected value.

    The mean for a lognormal random variable is

    Mean for a lognormal distribution.

    where μ is the location parameter and σ > 0 is the scale parameter. According to the definition, the natural logarithm of a random variable from a lognormal distribution follows a normal distribution.

    Installation

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

    Usage

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

    mean( mu, sigma )

    Returns the expected value for a lognormal distribution with location mu and scale sigma.

    var y = mean( 2.0, 1.0 );
    // returns ~12.182
    
    y = mean( 0.0, 1.0 );
    // returns ~1.649
    
    y = mean( -1.0, 4.0 );
    // returns ~1096.633

    If provided NaN as any argument, the function returns NaN.

    var y = mean( NaN, 1.0 );
    // returns NaN
    
    y = mean( 0.0, NaN );
    // returns NaN

    If provided sigma <= 0, the function returns NaN.

    var y = mean( 0.0, 0.0 );
    // returns NaN
    
    y = mean( 0.0, -1.0 );
    // returns NaN

    Examples

    var randu = require( '@stdlib/random-base-randu' );
    var mean = require( '@stdlib/stats-base-dists-lognormal-mean' );
    
    var sigma;
    var mu;
    var y;
    var i;
    
    for ( i = 0; i < 10; i++ ) {
        mu = ( randu()*10.0 ) - 5.0;
        sigma = randu() * 20.0;
        y = mean( mu, sigma );
        console.log( 'µ: %d, σ: %d, E(X;µ,σ): %d', mu.toFixed( 4 ), sigma.toFixed( 4 ), y.toFixed( 4 ) );
    }

    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 © 2016-2022. The Stdlib Authors.

    Install

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

    Homepage

    stdlib.io

    DownloadsWeekly Downloads

    96

    Version

    0.0.6

    License

    Apache-2.0

    Unpacked Size

    47.6 kB

    Total Files

    10

    Last publish

    Collaborators

    • stdlib-bot
    • kgryte
    • planeshifter
    • rreusser