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Fisher's F
F distribution constructor.
Installation
npm install @stdlib/stats-base-dists-f-ctor
Usage
var F = require( '@stdlib/stats-base-dists-f-ctor' );
F( [d1, d2] )
Returns a F distribution object.
var f = new F();
var mu = f.mean;
// returns NaN
By default, d1 = 1.0
and d2 = 1.0
. To create a distribution having a different d1
(numerator degrees of freedom) and d2
(denominator degrees of freedom), provide the corresponding arguments.
var f = new F( 2.0, 4.0 );
var mu = f.mean;
// returns 2.0
f
A F distribution object has the following properties and methods...
Writable Properties
f.d1
Numerator degrees of freedom of the distribution. d1
must be a positive number.
var f = new F();
var d1 = f.d1;
// returns 1.0
f.d1 = 3.0;
d1 = f.d1;
// returns 3.0
f.d2
Denominator degrees of freedom of the distribution. d2
must be a positive number.
var f = new F( 2.0, 4.0 );
var d2 = f.d2;
// returns 4.0
f.d2 = 3.0;
d2 = f.d2;
// returns 3.0
Computed Properties
F.prototype.entropy
Returns the differential entropy.
var f = new F( 4.0, 12.0 );
var entropy = f.entropy;
// returns ~1.12
F.prototype.kurtosis
Returns the excess kurtosis.
var f = new F( 4.0, 12.0 );
var kurtosis = f.kurtosis;
// returns ~26.143
F.prototype.mean
Returns the expected value.
var f = new F( 4.0, 12.0 );
var mu = f.mean;
// returns 1.2
F.prototype.mode
Returns the mode.
var f = new F( 4.0, 12.0 );
var mode = f.mode;
// returns ~0.429
F.prototype.skewness
Returns the skewness.
var f = new F( 4.0, 12.0 );
var skewness = f.skewness;
// returns ~3.207
F.prototype.stdev
Returns the standard deviation.
var f = new F( 4.0, 12.0 );
var s = f.stdev;
// returns ~1.122
F.prototype.variance
Returns the variance.
var f = new F( 4.0, 12.0 );
var s2 = f.variance;
// returns 1.26
Methods
F.prototype.cdf( x )
Evaluates the cumulative distribution function (CDF).
var f = new F( 2.0, 4.0 );
var y = f.cdf( 0.5 );
// returns ~0.36
F.prototype.pdf( x )
Evaluates the probability density function (PDF).
var f = new F( 2.0, 4.0 );
var y = f.pdf( 0.8 );
// returns ~0.364
F.prototype.quantile( p )
Evaluates the quantile function at probability p
.
var f = new F( 2.0, 4.0 );
var y = f.quantile( 0.5 );
// returns ~0.828
y = f.quantile( 1.9 );
// returns NaN
Examples
var F = require( '@stdlib/stats-base-dists-f-ctor' );
var f = new F( 3.0, 5.0 );
var mu = f.mean;
// returns ~1.667
var mode = f.mode;
// returns ~0.238
var s2 = f.variance;
// returns ~11.111
var y = f.cdf( 0.8 );
// returns ~0.455
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.