@stdlib/stats-base-dists-pareto-type1-stdev
v0.2.2
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Pareto (Type I) distribution standard deviation.
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Standard Deviation
Pareto (Type I) distribution standard deviation.
The standard deviation for a Pareto (Type I) random variable is
where α > 0
is the shape parameter and β > 0
is the scale parameter.
Installation
npm install @stdlib/stats-base-dists-pareto-type1-stdev
Usage
var stdev = require( '@stdlib/stats-base-dists-pareto-type1-stdev' );
stdev( alpha, beta )
Returns the standard deviation of a Pareto (Type I) distribution with parameters alpha
(shape parameter) and beta
(scale parameter).
var v = stdev( 2.5, 1.0 );
// returns ~1.491
v = stdev( 4.0, 12.0 );
// returns ~5.657
v = stdev( 8.0, 2.0 );
// returns ~0.33
If provided NaN
as any argument, the function returns NaN
.
var v = stdev( NaN, 2.0 );
// returns NaN
v = stdev( 2.0, NaN );
// returns NaN
If provided 0 < alpha <= 2
, the function returns +Infinity
.
var v = stdev( 0.5, 2.0 );
// returns Infinity
v = stdev( 1.5, 1.0 );
// returns Infinity
If provided alpha <= 0
, the function returns NaN
.
var v = stdev( 0.0, 1.0 );
// returns NaN
v = stdev( -1.0, 1.0 );
// returns NaN
If provided beta <= 0
, the function returns NaN
.
var v = stdev( 1.0, 0.0 );
// returns NaN
v = stdev( 1.0, -1.0 );
// returns NaN
Examples
var randu = require( '@stdlib/random-base-randu' );
var EPS = require( '@stdlib/constants-float64-eps' );
var stdev = require( '@stdlib/stats-base-dists-pareto-type1-stdev' );
var alpha;
var beta;
var v;
var i;
for ( i = 0; i < 10; i++ ) {
alpha = ( randu()*10.0 ) + EPS;
beta = ( randu()*10.0 ) + EPS;
v = stdev( alpha, beta );
console.log( 'α: %d, β: %d, Var(X;α,β): %d', alpha.toFixed( 4 ), beta.toFixed( 4 ), v.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.
Community
License
See LICENSE.
Copyright
Copyright © 2016-2024. The Stdlib Authors.