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Geometric
Geometric distribution constructor.
Installation
npm install @stdlib/stats-base-dists-geometric-ctor
Usage
var Geometric = require( '@stdlib/stats-base-dists-geometric-ctor' );
Geometric( [p] )
Returns a geometric distribution object.
var geometric = new Geometric();
var mean = geometric.mean;
// returns 1.0
By default, p = 0.5
. To create a distribution having a different success probability p
, provide a parameter value.
var geometric = new Geometric( 0.2 );
var mean = geometric.mean;
// returns 4.0
geometric
A geometric distribution object has the following properties and methods...
Writable Properties
geometric.p
Success probability of the distribution. p
must be a probability.
var geometric = new Geometric( 0.2 );
var p = geometric.p;
// returns 0.2
geometric.p = 0.3;
p = geometric.p;
// returns 0.3
Computed Properties
Geometric.prototype.entropy
Returns the differential entropy.
var geometric = new Geometric( 0.4 );
var entropy = geometric.entropy;
// returns ~1.683
Geometric.prototype.kurtosis
Returns the excess kurtosis.
var geometric = new Geometric( 0.4 );
var kurtosis = geometric.kurtosis;
// returns ~6.267
Geometric.prototype.mean
Returns the median.
var geometric = new Geometric( 0.4 );
var mu = geometric.mean;
// returns ~1.5
Geometric.prototype.median
Returns the median.
var geometric = new Geometric( 0.4 );
var median = geometric.median;
// returns 1.0
Geometric.prototype.mode
Returns the mode.
var geometric = new Geometric( 0.4 );
var mode = geometric.mode;
// returns 0.0
Geometric.prototype.skewness
Returns the skewness.
var geometric = new Geometric( 0.4 );
var skewness = geometric.skewness;
// returns ~2.066
Geometric.prototype.stdev
Returns the standard deviation.
var geometric = new Geometric( 0.4 );
var s = geometric.stdev;
// returns ~1.936
Geometric.prototype.variance
Returns the variance.
var geometric = new Geometric( 0.4 );
var s2 = geometric.variance;
// returns ~3.75
Methods
Geometric.prototype.cdf( x )
Evaluates the cumulative distribution function (CDF).
var geometric = new Geometric( 0.2 );
var y = geometric.cdf( 0.5 );
// returns ~0.2
Geometric.prototype.logcdf( x )
Evaluates the natural logarithm of the cumulative distribution function (logCDF).
var geometric = new Geometric( 0.2 );
var y = geometric.logcdf( 0.5 );
// returns ~-1.609
Geometric.prototype.logpmf( x )
Evaluates the natural logarithm of the probability mass function (logPMF).
var geometric = new Geometric( 0.2 );
var y = geometric.logpmf( 3.0 );
// returns ~-2.279
y = geometric.logpmf( 2.3 );
// returns -Infinity
Geometric.prototype.mgf( t )
Evaluates the moment-generating function (MGF).
var geometric = new Geometric( 0.2 );
var y = geometric.mgf( 0.1 );
// returns ~1.908
Geometric.prototype.pmf( x )
Evaluates the probability mass function (PMF).
var geometric = new Geometric( 0.2 );
var y = geometric.pmf( 3.0 );
// returns ~0.102
y = geometric.pmf( 2.3 );
// returns 0.0
Geometric.prototype.quantile( p )
Evaluates the quantile function at probability p
.
var geometric = new Geometric( 0.2 );
var y = geometric.quantile( 0.5 );
// returns 3.0
y = geometric.quantile( 1.9 );
// returns NaN
Examples
var Geometric = require( '@stdlib/stats-base-dists-geometric-ctor' );
var geometric = new Geometric( 0.5 );
var mu = geometric.mean;
// returns 1.0
var mode = geometric.mode;
// returns 0.0
var s2 = geometric.variance;
// returns 2.0
var y = geometric.cdf( 2.0 );
// returns 0.875
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.