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Logistic

Logistic distribution constructor.

Installation

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

Alternatively,

• To load the package in a website via a script tag without installation and bundlers, use the ES Module available on the esm branch (see README).
• If you are using Deno, visit the deno branch (see README for usage intructions).
• For use in Observable, or in browser/node environments, use the Universal Module Definition (UMD) build available on the umd branch (see README).

The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

Usage

var Logistic = require( '@stdlib/stats-base-dists-logistic-ctor' );

Logistic( [mu, s] )

Returns a logistic distribution object.

var logistic = new Logistic();

var mu = logistic.mean;
// returns 0.0

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

var logistic = new Logistic( 2.0, 4.0 );

var mu = logistic.mean;
// returns 2.0

---

logistic

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

Writable Properties

logistic.mu

Location parameter of the distribution.

var logistic = new Logistic();

var mu = logistic.mu;
// returns 0.0

logistic.mu = 3.0;

mu = logistic.mu;
// returns 3.0

logistic.s

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

var logistic = new Logistic( 2.0, 4.0 );

var s = logistic.s;
// returns 4.0

logistic.s = 3.0;

s = logistic.s;
// returns 3.0

---

Computed Properties

Logistic.prototype.entropy

Returns the differential entropy.

var logistic = new Logistic( 4.0, 12.0 );

var entropy = logistic.entropy;
// returns ~4.485

Logistic.prototype.kurtosis

Returns the excess kurtosis.

var logistic = new Logistic( 4.0, 12.0 );

var kurtosis = logistic.kurtosis;
// returns 1.2

Logistic.prototype.mean

Returns the expected value.

var logistic = new Logistic( 4.0, 12.0 );

var mu = logistic.mean;
// returns 4.0

Logistic.prototype.median

Returns the median.

var logistic = new Logistic( 4.0, 12.0 );

var median = logistic.median;
// returns 4.0

Logistic.prototype.mode

Returns the mode.

var logistic = new Logistic( 4.0, 12.0 );

var mode = logistic.mode;
// returns 4.0

Logistic.prototype.skewness

Returns the skewness.

var logistic = new Logistic( 4.0, 12.0 );

var skewness = logistic.skewness;
// returns 0.0

Logistic.prototype.stdev

Returns the standard deviation.

var logistic = new Logistic( 4.0, 12.0 );

var s = logistic.stdev;
// returns ~21.766

Logistic.prototype.variance

Returns the variance.

var logistic = new Logistic( 4.0, 12.0 );

var s2 = logistic.variance;
// returns ~473.741

---

Methods

Logistic.prototype.cdf( x )

Evaluates the cumulative distribution function (CDF).

var logistic = new Logistic( 2.0, 4.0 );

var y = logistic.cdf( 0.5 );
// returns ~0.407

Logistic.prototype.logcdf( x )

Evaluates the natural logarithm of the cumulative distribution function (CDF).

var logistic = new Logistic( 2.0, 4.0 );

var y = logistic.logcdf( 2.0 );
// returns ~-0.693

Logistic.prototype.logpdf( x )

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

var logistic = new Logistic( 2.0, 4.0 );

var y = logistic.logpdf( 0.8 );
// returns ~-2.795

Logistic.prototype.mgf( t )

Evaluates the moment-generating function (MGF).

var logistic = new Logistic( 2.0, 4.0 );

var y = logistic.mgf( 0.2 );
// returns ~6.379

Logistic.prototype.pdf( x )

Evaluates the probability density function (PDF).

var logistic = new Logistic( 2.0, 4.0 );

var y = logistic.pdf( 2.0 );
// returns 0.0625

Logistic.prototype.quantile( p )

Evaluates the quantile function at probability p.

var logistic = new Logistic( 2.0, 4.0 );

var y = logistic.quantile( 0.5 );
// returns 2.0

y = logistic.quantile( 1.9 );
// returns NaN

---

Examples

var Logistic = require( '@stdlib/stats-base-dists-logistic-ctor' );

var logistic = new Logistic( 2.0, 4.0 );

var mean = logistic.mean;
// returns 2.0

var median = logistic.median;
// returns 2.0

var s2 = logistic.variance;
// returns ~52.638

var y = logistic.cdf( 0.8 );
// returns ~0.426

---

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 © 2016-2024. The Stdlib Authors.