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Beta Prime
Beta prime distribution constructor.
Installation
npm install @stdlib/stats-base-dists-betaprime-ctor
Usage
var BetaPrime = require( '@stdlib/stats-base-dists-betaprime-ctor' );
BetaPrime( [alpha, beta] )
Returns a beta prime distribution object.
var betaprime = new BetaPrime();
var mode = betaprime.mode;
// returns 0.0
By default, alpha = 1.0
and beta = 1.0
. To create a distribution having a different alpha
(first shape parameter) and beta
(second shape parameter), provide the corresponding arguments.
var betaprime = new BetaPrime( 2.0, 4.0 );
var mu = betaprime.mean;
// returns ~0.667
betaprime
A beta prime distribution object has the following properties and methods...
Writable Properties
betaprime.alpha
First shape parameter of the distribution. alpha
must be a positive number.
var betaprime = new BetaPrime();
var alpha = betaprime.alpha;
// returns 1.0
betaprime.alpha = 3.0;
alpha = betaprime.alpha;
// returns 3.0
betaprime.beta
Second shape parameter of the distribution. beta
must be a positive number.
var betaprime = new BetaPrime( 2.0, 4.0 );
var b = betaprime.beta;
// returns 4.0
betaprime.beta = 3.0;
b = betaprime.beta;
// returns 3.0
Computed Properties
BetaPrime.prototype.kurtosis
Returns the excess kurtosis.
var betaprime = new BetaPrime( 4.0, 12.0 );
var kurtosis = betaprime.kurtosis;
// returns ~5.764
BetaPrime.prototype.mean
Returns the expected value.
var betaprime = new BetaPrime( 4.0, 12.0 );
var mu = betaprime.mean;
// returns ~0.364
BetaPrime.prototype.mode
Returns the mode.
var betaprime = new BetaPrime( 4.0, 12.0 );
var mode = betaprime.mode;
// returns ~0.231
BetaPrime.prototype.skewness
Returns the skewness.
var betaprime = new BetaPrime( 4.0, 12.0 );
var skewness = betaprime.skewness;
// returns ~1.724
BetaPrime.prototype.stdev
Returns the standard deviation.
var betaprime = new BetaPrime( 4.0, 12.0 );
var s = betaprime.stdev;
// returns ~0.223
BetaPrime.prototype.variance
Returns the variance.
var betaprime = new BetaPrime( 4.0, 12.0 );
var s2 = betaprime.variance;
// returns ~0.05
Methods
BetaPrime.prototype.cdf( x )
Evaluates the cumulative distribution function (CDF).
var betaprime = new BetaPrime( 2.0, 4.0 );
var y = betaprime.cdf( 0.5 );
// returns ~0.539
BetaPrime.prototype.logcdf( x )
Evaluates the natural logarithm of the cumulative distribution function (CDF).
var betaprime = new BetaPrime( 2.0, 4.0 );
var y = betaprime.logcdf( 0.5 );
// returns ~-0.618
BetaPrime.prototype.logpdf( x )
Evaluates the natural logarithm of the probability density function (PDF).
var betaprime = new BetaPrime( 2.0, 4.0 );
var y = betaprime.logpdf( 0.8 );
// returns ~-0.754
BetaPrime.prototype.pdf( x )
Evaluates the probability density function (PDF).
var betaprime = new BetaPrime( 2.0, 4.0 );
var y = betaprime.pdf( 0.8 );
// returns ~0.47
BetaPrime.prototype.quantile( p )
Evaluates the quantile function at probability p
.
var betaprime = new BetaPrime( 2.0, 4.0 );
var y = betaprime.quantile( 0.5 );
// returns ~0.457
y = betaprime.quantile( 1.9 );
// returns NaN
Examples
var BetaPrime = require( '@stdlib/stats-base-dists-betaprime-ctor' );
var betaprime = new BetaPrime( 2.0, 4.0 );
var mu = betaprime.mean;
// returns ~0.667
var mode = betaprime.mode;
// returns 0.2
var s2 = betaprime.variance;
// returns ~0.556
var y = betaprime.cdf( 0.8 );
// returns ~0.735
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.